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1.
O. V. Vlasenko A. V. Dovgan’ A. I. Pilyavskii V. A. Maisky A. V. Maznichenko 《Neurophysiology》2009,41(2):148-156
The expression of early c-fos gene (marker of neuronal activation) and NADPH-diaphorase reactivity (NADPH-dr) was studied in various hypothalamic structures
of rats in the norm, in the state of starvation, and after realization of long-lasting (repeated 4 to 12 times per minute
for 30 min) motivated stereotyped food-procuring forelimb movements. In rats in the starving state, as compared with the control,
the densities (number of units within a 200 × 200 μm2 test area of a 40-μm-thick slice) of Fos-immunoreactive (Fos-ir) neurons in the parvicellular part of the paraventricular
nucleus (Ра), supraoptic (SO), and medial preoptic (МРО) nuclei, anterior hypothalamic region (АН), and lateral hypothalamic nucleus (LH) were significantly greater (Р < 0.05) than in the control. In the dorsomedial (DMD) and ventromedial (VMHD) hypothalamic nuclei, this index did not differ from control values. After the performance of intense unilateral operant
movements, higher densities of labeled neurons (as compared with that in control and starving animals) were observed in the
PаAP, SO, МРО, and DMD, while smaller densities were observed in the LH and VMH. NADPH-dr neurons (i.e., NO synthase-containing cells) were observed in many hypothalamic nuclei; the maximum density of
such NO-generating neurons was found in the Pa, SO, MPO, and DMD. The overwhelming majority of Fos-ir and NADPH-dr neurons in neurons was observed after realization of stereotyped food-procuring
movements in the Ра and SO. This specificity of changes in the number of Fos-irand NADPH-dr neurons in the hypothalamic nuclei reflects, perhaps, the
involvement of these structures in the control of autonomic functions in the course of realization of operant reflexes and
adaptation of the function of the cardiovascular system to the corresponding intense physical and emotional loading. 相似文献
2.
A. V. Dovgan’ O. V. Vlasenko V. A. Maisky A. I. Pilyavskii A. V. Maznichenko 《Neurophysiology》2009,41(1):28-36
We estimated in rats the expression of early gene c-fos (marker of neuronal activation) and NADPH-diaphorase activity (NO-synthase marker) in the limbic structures of the basal
forebrain and in the hypothalamus. Estimations were performed in the norm, in the state of starvation, and after realization
of long-lasting (repeated 4 to 12 times per minute for 30 min) motivated stereotyped food-procuring forelimb movements. In
food-deprived animals, a significantly greater (Р < 0.05), as compared with the control, number of Fos-immunoreactive (Fos-ir) and NADPH-diaphorase-reactive (NADPH-dr) neurons
was observed in limbic structures, namely in the medial septum (MS), nuclei of the vertical and horizontal branches of the diagonal fascia (VDB and НDB), magnocellular preoptic nucleus (MCPO), complex of the substantia innominata−basal nucleus of Meynert of the pallidum, SI-GP(B), as well as in the laterodorsal tegmental nucleus (LDTg), medial part of the pallidum (MGP), paraventricular and lateral nuclei of the hypothalamus (Pa and LH), and islands of Calleja (ICj and ICjM). In the limbic structures and pontine nuclei of rats of the experimental group (that performed operant movements), greater
mean densities of labeled neurons were found in the succession LDTg < SI < MCPO < GP(B) < MS < VDB < HDB. The maximum mean density of Fos-ir neurons (13.8 ± 0.9 labeled nuclei within 200 × 200 μm2 area) was found in the HDB. In the hypothalamic nuclei of starving rats, c-fos expression was two times higher than that in the control. After realization of operant movements, the intensity of expression
in the LH was somewhat smaller, while in the Ра it was higher. The maximum density of NADPH-dr neurons was observed in the Pa (303.4 ± 18.7 cells), in the ICj and ICjM (287 ± 11.6 and 260 ± 8.7 neurons, respectively), and in the MGP (93 ± 6.7 labeled cells). When analyzing the distribution of labeled neurons in experimental rats, we found high densities
of double-labeled cells (Fos + NADPH-d positivity) in the Pa, MGP, ICj, and ICjM. Such specificity of changes in the c-fos expression and NADPH-d reactivity in the hypothalamus correlates, perhaps, with the formation of motivation signals related
to a delay in food accessibility and supply of food. Modifications of neuronal activity in limbic structures reflect involvement
of the latter in the formation of motor programs for food-procuring movements and their realization.
Neirofiziologiya/Neurophysiology, Vol. 41, No. 1, pp. 32–40, January–February, 2009. 相似文献
3.
A comparative study of mmunoreactivity with respect to c-Fos protein in the motor (zones М1 and М2), medial prefrontal (PrL and IL), and cingular (Cg1 and Cg2) cortices allowed us to find significant differences between the intensities of expression of gene c-fos in these cortical regions in control rats (group 1) and animals trained to perform catching of food globules by the forelimb
(i.e., realizing an operant food-procuring reflex, group 2). The density of distribution of Fos-immunoreactive (Fos-ir) neurons
in rats of group 2 in motor and limbic cortical zones at +2.2 to +0.2 levels rostrally from the bregma were significantly
lower than in control rats (Р < 0.05). In animals of group 2, we also found significantly greater numbers of Fos-ir neurons in the contralateral (with respect
to the active extremity) zones of the cortex at all examined levels. These changes are probably related to functional changes
in the cortex resulting from learning of motor habits in the course of training sessions for stabilization of the operant
reflex. Histochemical estimation of the NADPH-diaphorase (NADPH-d) activity in the motor and limbic cortex showed that, in
rats of both groups, the maximum number of labeled interneurons per slice in the М1 zone were observed in layers II/III, V, and VI (5.6 ± 0.4, 6.4 ± 0.5, and 14.0 ± 0.8, respectively, within 200 × 200 μm2 areas). In the limbic cortex, NADPH-d-reactive (NADPH-d-r) interneurons were also met in layers II/III, V, and VI. Cortical
NADPHd-r neurons with the Fos-ir nuclei were not found. The presence of spatial associations of the somata or processes of
NADPH-d-r neurons with intraparenchimal arterioles and microvessels was a typical feature of the distribution of NADPH-d-reactivity
in the М1 and М2 zones, as well as in Cg1, Cg2, PrL, and IL. The following succession of the density of neurovascular associations was observed: Cg1 > Cg2 > М1 > М2 > > PrL. As is supposed, NADPH-d-r neurons (i.e., cells generating NO) are involved in the control of regional blood flow in the
studied cortical regions.
Neirofiziologiya/Neurophysiology, Vol. 40, No. 4, pp. 348–358, July–August, 2008. 相似文献
4.
V. M. Moroz 《Neurophysiology》2002,34(6):395-405
We studied the roles of the cerebellum and caudate nuclei in the programming and control of ballistic movements. An experimental model of operant food-procuring movements of the rats was used; the activity of single neurons of the above structures was recorded in the course of these motor performances. To evaluate the impact of the cerebellar–caudate interaction on the process of control of the ballistic (centrally programmed) components of food-procuring motor performance, we also recorded modifications of the neuronal activity in one of the above-mentioned structures induced by electrical extrastimulation of another structure in the course of realization of the above components. It is demonstrated that the cerebellum and, in particular, its dentate nuclei are involved in the programming of ballistic food-procuring movements. Neurons of the caudate nuclei play a significant role in the immediate preparation for and subsequent current control of stereotyped ballistic movements. The high plastic properties of the cerebellar neurons manifested in the process of control of ballistic food-procuring movements are proved. 相似文献
5.
A. V. Dovgan’ O. V. Vlasenko A. V. Maznychenko A. I. Pilyavskii V. A. Maiskii 《Neurophysiology》2011,43(3):244-247
We studied manifestations of increased neuronal activity in the limbic structures of the rat brain related to realizations
of operant reflexes by the animals. After rats had performed repeated operant foodprocuring movements, the mean numbers of
Fos-immunoreactive neurons within sections of the central and basolateral amygdalar nuclei, insular cortex, substantia innominata, and paraventricular hypothalamic nucleus significantly exceeded the control values. In the ipsilateral (with respect to
the working forelimb) central nucleus of the amygdala, the mean number of such neurons within a 40-μm-thick slice was nearly
an order of magnitude greater than in the control (42.2 ± 2.4 and 4.5 ± 0.4 labeled units, respectively). In the agranular
insular and granular/disgranular cortical zones at the contralateral site, the numbers of labeled neurons exceeded control
values by about three times (94.6 ± 8.2 vs 31.6 ± 2.2 and 103.5 ± 4.5 vs 39.6 ± ± 2.4 immunopositive cells, respectively). These findings confirm the hypothesis on the direct involvement of the
subcortical structures and limbic cortex zones in the control of somato-cardiovascular integration during the performance
of operant reflexes by the animals. 相似文献
6.
We studied the impulse activity of neurons of the basal and lateral amygdalar nuclei generated when experimental animals (rats) performed fast stereotyped food-procuring movements by the forelimb. Within the basolateral amygdala, there are neurons whose activity is related to different stages of getting off the food, and according to the characteristics of their spiking these neurons should be divided into a number of subpopulations. Activation forestalling the movement initiation by 0.5-1.0 sec was observed in most neurons of the basolateral amygdala; this is considered a manifestation of excitation related to a motivation component of the food-procuring behavior. Activation of amygdalar neurons following movement initiation can result from generation in this structure of additional excitation necessary for successful performance of a complete food-procuring motor cycle. 相似文献
7.
V. V. Sachenko 《Neurophysiology》1996,28(6):240-245
Effects of injections of blockers of the monoaminergic receptor structures into thecentrum medianum-nucl. parafascicularis (CM-Pf) on the activity of neurons in the motor thalamic nuclei (VA-VL) were studied in chronic experiments on awake cats. The animals were trained to perform an operant placing reflex by the forelimb. Injection of a-adrenoblocker, anapriline, into theCM-Pf resulted in enhancement of background activity of neurons of the motor thalamus and facilitation of their spike responses related to conditioned and unconditioned reflex movements. Application of a blocker of serotonin receptors, lysergoamide, evoked opposite changes in the neuronal activity in theVA-VL nuclei: depression of background activity, facilitation of inhibitory processes, and suppression of evoked activity related to conditioned and unconditioned movements. It is supposed that the monoaminergic system of thelocus coeruleus exerts a suppressing influence on the motor thalamus via theCM-Pf complex, while the system of the raphe nuclei facilitates motor thalamic structures.Neirofiziologiya/Neurophysiology, Vol. 28, No. 6, pp. 305–311, November–December, 1996. 相似文献
8.
L. N. Shapoval O. V. Dmytrenko L. S. Pobegailo L. G. Stepanenko V. F. Sagach 《Neurophysiology》2007,39(4-5):343-346
In acute experiments on anesthetized rats, we studied the effects of modulation of the mitochondrial permeability in medullary
cardiovascular neurons (nucl. tractus solitarii, NTS, nucl. ambiguus, AMB, paramedian reticular nucleus, PMn, and lateral reticular nucleus, LRN) on the systemic arterial pressure (SAP). We
were the first to show that the mitochondrial permeability is essential for medullary cardiovascular control. An increase
in the mitochondrial permeability with injections of an inductor of mitochondrial transition pore opening, phenylarsine oxide
(PAO, 0.5 to 504 nmol), into the medullary nuclei resulted in long-lasting decreases in the SAP; at high doses of PAO, these
drops could be irreversible and led to the animal’s death. Injections of an inhibitor of mitochondrial transition pore opening,
melatonin (0.7 to 70.0 nmol), into the medullary nuclei induced dose-dependent increases in the SAP. Melatonin and L-arginine
were shown to demonstrate neuroprotective effects due to their ability to attenuate the consequences of increased mitochondrial
permeability in medullary cardiovascular neurons.
Neirofiziologiya/Neurophysiology, Vol. 39, Nos. 4/5, pp. 392–395, July–October, 2007. 相似文献
9.
Using a histochemical technique, we examined distribution of the neurons containing a marker of nitric oxide synthase (NOS),
NADPH-diaphorase (NADPH-d), on frontal slices of the medulla and upper cervical spinal segments of 4-day-old rats. It was
demonstrated that NADPH-d-positive cells are present within the dorsal and ventral medullary respiratory groups. The highest
density of the labeled middle-size multipolar neurons (27.9±2.6 cells per 0.1 mm2 of the slice) was observed in the rostral part of the ventral respiratory group, within the reticular lateral paragigantocellular
nucleus. Similar NADPH-d-positive neurons were also observed in other reticular formation structures: rostroventrolateral
reticular, gigantocellular, and ventral medullary nuclei, and in the ventral part of the paramedial nucleus. There were no
labeled neurons in the lateral reticular nucleus. Single small and medium-size labeled neurons were found at all rostro-caudal
levels of thenucl. ambiguous (nuclei retrofacialis, ambiguous, andretroam-biguous). Groups of NADPH-d-positive neurons were also revealed within the dorsal respiratory group, along the whole length of thenucl. tractus solitarii (mostly in its ventrolateral parts). Single labeled neurons were also observed in thenucl. n. hypoglossi, and their groups were observed in the dorsal motor part of thenucl. n. vagus. Involvement of the structures containing NADPH-d-positive neurons in the processes related to generation of the respiratory
activity is discussed. Our neuroanatomical experiments prove that in early postnatal mammals NO is actively involved in generation
and regulation of the medullary respiratory rhythm.
Neirofiziologiya/Neurophysiology, Vol. 32, No. 2, pp. 128–136, March–April, 2000. 相似文献
10.
We estimated expression of the c-fos gene (a marker of increase in neuronal activity) and manifestations of the histochemical reaction to NADPH-diaphorase (a
marker of NO-generating neurons) in the medial prefrontal cortex (MPFC) and forebrain limbic structures of rats in the norm, in the state of starvation, and during realization of long-lasting
(60 min) periodic (several times per minute) food-procuring movements of the forelimb. The starvation state or realization
of motivated stereotyped forelimb movements were related to significant bilateral increases (P < 0.05) in the levels of c-fos expression in the anterior olfactory (AOP) and cortical (ACo) nuclei and the central (Ce) and basolateral (BLA) nuclei of the amygdala, and also in the pyriform (Pyr), prelimbic (PrL), and inferior limbic (IL) cortices. The described findings demonstrate that the high Fos immunoreactivity in the MPFC and amygdalar structures is related to the motivation state in animals and reflects the active involvement of limbic cerebral
structures in the formation of motor programs and also in the stabilization and realization of operant reflexes.
Neirofiziologiya/Neurophysiology, Vol. 40, No. 3, pp. 256–259, May–June, 2008. 相似文献
11.
We tried to answer the question to what extent neurons in the tectum of the superior colliculus (SC) of the cat and in regions of the mesencephalic reticular formation (MRF) localized more ventrally are involved in the
control of movements of the limbs. The impulse activity of neurons of the above-mentioned structures was recorded in animals
performing targeted operated food-procuring movements by their forelimbs (pressing the pedal). As was found, neurons with
impulse reactions correlating with forelimb movements are rather numerous in the SC and adjacent MRF, and there are several
groups of neurons, whose impulse responses reached their maxima within different phases of the movements. These were neurons
with peaks of the discharge frequency coinciding with the target-reaching movement, with the moment of touching the pedal,
with pressing the pedal, and with the development of the muscle force counteracting the forced withdrawal of the limb toward
the initial position. Such specific patterns of the responses of different neurons of the SC and neighboring MRF are indicative
of a rather specific involvement of the above structures in the control of forelimb movements in cats.
Neirofiziologiya/Neurophysiology, Vol. 39, No. 3, pp. 245–254, May–June, 2007. 相似文献
12.
L. N. Shapoval O. V. Dmytrenko L. S. Pobegailo L. G. Stepanenko V. F. Sagach 《Neurophysiology》2007,39(3):201-212
In acute experiments on normotensive rats and those with genetically determined hypertension (urethane anesthesia), we studied
hemodynamic effects resulting from modulation of the activities of neuronal NO synthase (NOS-1), arginase II, and superoxide
dismutase, and also of the mitochondrial permeability in medullary cardiovascular neurons. Unilateral microinjections of either
a nitric oxide (NO) donor, sodium nitroprusside, or a substrate for endogenous NO synthesis, L-arginine, into the medullary
cardiovascular nuclei (nucl. tractus solitarius, NTS, nucl. ambiguous, AMB, paramedian nucleus, PMn, and lateral reticular nucleus LRN) were shown to induce hemodynamic responses with rather similar dynamics in both normotensive and spontaneously hypertensive
rats, although in the latter the reactions were more intense. Injections of an antagonist of NOS-1, NG nitro-L-arginine (L-NNA), into the medullary nuclei under study in spontaneously hypertensive rats resulted in shifts of
the systemic arterial pressure (SAP), which did not differ dramatically from those observed in normotensive animals. The data
obtained serve as the background for the suggestion that the functional activity of NOS-1 is not fundamentally impaired under
hypertension conditions, but, probably, the amount of the substrate for adequate synthesis of NO via the NO-synthase pathway
of metabolism of L-arginine is insufficient. Considering this, we examined the functional activity of arginase, an enzyme
that also, similarly to NOS, uses L-arginine for metabolic transformation. Injections of antagonists of arginase, norvaline
or α-difluoromethylornithine hydrochloride (DFMO), into populations of the medullary neurons under study induced similar shifts
of the SAP in normotensive and spontaneously hypertensive rats, and those responses did not differ significantly from the
effects of inhibition of the NOS-1 activity. Thus, both the above-mentioned enzymes are potentially active in normotensive
and spontaneously hypertensive rats; so, a possibility for their competition for L-arginine in certain situations does exist.
Modulation of the mitochondrial permeability in medullary cardiovascular neurons in normotensive and spontaneously hypertensive
rats induced significant hemodynamic effects. In particular, an increase in the mitochondrial permeability in the medullary
cardiovascular nuclei by injections of an inductor of mitochondrial permeability transition pore (mPTP) opening, phenylarsine
oxide (PAO), was accompanied by SAP drops in both normotensive and spontaneously hypertensive rats; the effects were dose-dependent
and, in some cases, irreversible. A decrease in the mitochondrial permeability in the neurons under study by injections of
an inhibitor of mPTP, melatonin, induced mostly hypertensive responses, although in some experiments we observed hypotensive
and two-phase responses.
Neirofiziologiya/Neurophysiology, Vol. 39, No. 3, pp. 232–244, May–June, 2007. 相似文献
13.
I.-Hsien Tsu C.-Y. Huang J.-L. Garcia Bharat K. C. Patel Jean-Luc Cayol Larry Baresi Robert A. Mah 《Archives of microbiology》1998,170(4):313-317
A new halotolerant Desulfovibrio, strain CVLT (T = type strain), was isolated from a solar saltern in California. The curved, gram-negative, nonsporeforming cells (0.3
× 1.0–1.3 μm) occurred singly, in pairs, or in chains, were motile by a single polar flagellum and tolerated up to 12.5% NaCl.
Strain CVLT had a generation time of 60 min when grown in lactate-yeast extract medium under optimal conditions (37°C, pH 7.6, 2.5% NaCl).
It used lactate, pyruvate, cysteine, or H2/CO2 + acetate as electron donors, and sulfate, sulfite, thiosulfate, or fumarate as electron acceptors. Elemental sulfur, nitrate,
or oxygen were not used. Sulfite and thiosulfate were disproportionated to sulfate and sulfide. The G+C content of the DNA
was 62 mol%. Phylogenetic analysis revealed that Desulfovibrio fructosovorans was the nearest relative. Strain CVLT is clearly different from other Desulfovibrio species, and is designated Desulfovibrio senezii sp. nov. (DSM 8436).
Received: 27 February 1998 / Accepted: 15 June 1998 相似文献
14.
Emilie Sapin Anne Bérod Lucienne Léger Paul A. Herman Pierre-Hervé Luppi Christelle Peyron 《PloS one》2010,5(7)
We recently discovered, using Fos immunostaining, that the tuberal and mammillary hypothalamus contain a massive population of neurons specifically activated during paradoxical sleep (PS) hypersomnia. We further showed that some of the activated neurons of the tuberal hypothalamus express the melanin concentrating hormone (MCH) neuropeptide and that icv injection of MCH induces a strong increase in PS quantity. However, the chemical nature of the majority of the neurons activated during PS had not been characterized. To determine whether these neurons are GABAergic, we combined in situ hybridization of GAD67 mRNA with immunohistochemical detection of Fos in control, PS deprived and PS hypersomniac rats. We found that 74% of the very large population of Fos-labeled neurons located in the tuberal hypothalamus after PS hypersomnia were GAD-positive. We further demonstrated combining MCH immunohistochemistry and GAD67
in situ hybridization that 85% of the MCH neurons were also GAD-positive. Finally, based on the number of Fos-ir/GAD+, Fos-ir/MCH+, and GAD+/MCH+ double-labeled neurons counted from three sets of double-staining, we uncovered that around 80% of the large number of the Fos-ir/GAD+ neurons located in the tuberal hypothalamus after PS hypersomnia do not contain MCH. Based on these and previous results, we propose that the non-MCH Fos/GABAergic neuronal population could be involved in PS induction and maintenance while the Fos/MCH/GABAergic neurons could be involved in the homeostatic regulation of PS. Further investigations will be needed to corroborate this original hypothesis. 相似文献
15.
L. N. Shapoval L. S. Pobegailo L. G. Stepanenko O. V. Dmytrenko V. A. Bouryi V. F. Sagach 《Neurophysiology》2011,43(4):299-308
Physical inactivity can be considered one of the major risk factors related to cardiovascular diseases. There are reasons
to believe that the positive effect of exercise training is, to a large extent, mediated by modulation of the nervous control
of the circulation system. In our previous studies, we showed that modulation of mitochondrial permeability transition in
medullary cardiovascular neurons significantly contributes to the hemodynamic reactions in both the norm and a number of pathological
states. In this study, we examined in acute experiments on urethane-anesthetized rats the hemodynamic effects mediated by
either modulation of mitochondrial permeability transition in medullary neurons, or activation of neuronal NO synthase (NOS-1)
in these neuronal populations after preliminary moderate exercise training (everyday swimming sessions of increased duration
carried out for four weeks). It was shown that, after exercise training had been completed, the effects of injections of an
inductor of mitochondrial permeability transition pore (MPTP) opening, phenylarsine oxide (PAO, 0.5 to 1.5 nmol), into populations
of cardiovascular neurons in the medullary autonomic nuclei (nucl. tractus solitarius and paramedian and lateral reticular nuclei) were less expressed, as compared with those in control (untrained) animals.
The data obtained suggest that exercise training can exert a protective action on functional activity of medullary neurons
due to the decreased sensitivity of MPTPs to their opening. Injections of an inhibitor of MPTP opening, melatonin (0.7 to
2.1 nmol), into populations of medullary neurons under study in trained rats induced a decrease in the systemic arterial pressure
(SAP), in contrast to untrained animals demonstrating mostly hypertensive responses following injections of melatonin into
the above nuclei. Injections of an activator of neuronal NO synthase (NOS-1), L-arginine, into the medullary nuclei of swimming-trained
rats resulted in more expressed hemodynamic shifts than in control animals, which suggests an increase in the activity of
neuronal NO synthase in medullary neurons of such animals. 相似文献
16.
M. V. Yoltukhovskii 《Neurophysiology》1999,31(3):154-159
Movement-related electrical reactions of neuronal units localized in field 2 of the frontal cortex were studied in albino
rats performing fast food-procuring movements under conditions of unrestrained behavior. According to the temporal characteristics
of the changes in the neuronal spike activity, three types of reactions were classified: (i) activation that forestalled the
movement initiation for 1.0–1.5 sec; (ii) activation or inhibition forestalling this beginning for 0.20–0.26 sec; and (iii)
activation in the course of a performed movement. Considerations about the involvement of the neurons of various cortical
layers in the mechanisms of programing, switching on, and current control of the efficiency of performance of food-procuring
movements are proposed, and the role of the frontal cortex in these processes is discussed. 相似文献
17.
Neurons of the mammalian medullary respiratory center have complex patterns of electrophysiological behavior. Three typical phenomena associated with these patterns are spike frequency adaptation (SFA), delayed excitation (DE), and postinhibitory rebound (PIR). Although several nuclei are associated with the medullary-pontine respiratory center, we focused on neurons from two nuclei: (1) the ventral subnucleus of the nucleus tractus solitarius (vNTS) of the dorsal respiratory group and (2) the nucleus ambiguus (NA) of the ventral respiratory group. We developed a Hodgkin-Huxley (HH) type model of the typical medullary neuron that is capable of mimicking the discharge pattern of real neurons to a very high degree. Closer examination of typical data revealed, however, that there was not one type of medullary respiratory neuron, but at least three (types A, B
1, and B
2). We classified these neurons based on the electrophysiologic phenomena that they exhibited (type A exhibits DE but not PIR; types B
1 and B
2 exhibit PIR but not DE; all types are adapting). Our objective was to relate each of these well-known phenomena to specific ionic current mechanisms. In the model, three currents directly affect the phenomena investigated: the Ca2+-activated K
+ current, I
K,Ca
, controls peak and steady-state firing rates and the time constant of adaptation; the transient outward K
+ current, I
A, is responsible for all aspects of DE, including the dependence of delay on the magnitude and duration of conditioning hyperpolarization; and the hyperpolarization-activated current, I
h, elicits PIR and dictates its dependencies. We consider that our HH model represents a unifying structure, whereby different electrophysiological phenomena or discharge patterns can be emulated using different strengths of the component ionic membrane currents (particularly I
K,Ca
, I
A, and I
h). Moreover, its predictions suggest that the electrophysiological characteristics of medullary respiratory neurons, from different areas of the brainstem and even from different species, can be modeled using the same structural framework, wherein the specific properties of individual neurons are emulated by adjusting the strengths of key ionic membrane currents in the model. 相似文献
18.
19.
Using radioimmune techniques, we studied in detail the concentrations of -endorphin (-En), met- and leu-enkephalins (mE and lE, respectively), and substance P (SP) in a number of structures of the brainstem and forebrain of the cat. According to the proposed concept, these structures comprise the noci- and antinociceptive brain systems (NS and ANS). The above indices were measured in intact animals and in animals after nociceptive electrocutaneous stimulation (NECS) of the limb, stimulation of the ventrolateral zone of the midbrain central gray (vl SGC, a nociceptive midbrain structure), stimulation of the dorsolateral part of the above region and dorsal raphe nucleus (dl SGC and Rd, antinociceptive midbrain structures), and after combined stimulations (NECS preceded by conditioning stimulation of one of the above midbrain zones). We found that in the norm maximum SP concentrations were observed in the NS structures, while those of -En and mE were the highest in the hypothalamic nuclei belonging to the ANS and in its midbrain centers (dl SGC and Rd). Nociceptive ECS, stimulations of the studied midbrain zones, and combinations of these stimulations could result in specific and, in some cases, very significant (by an order of magnitude and more) shifts in the concentrations of the mentioned neuropeptides in the studied set of the central structures. After NECS and its combination with vl SGC stimulation, SP concentrations in the NS structures considerably increased, while -En and mE concentrations in the ANS components dropped. Stimulations of the dl SGC and Rd were accompanied by increases in the mE and -En levels and simultaneous drops in the SP concentrations in the ANS components; reciprocate shifts were observed within the NS. Changes in the lE level, which were related to the influences used, were less specific and mostly appeared as increases in this index in the structures of both the NS and ANS. Combinations of NECS with conditioning stimulations of the vl SGC, dl SGC, or Rd demonstrated that the latter exert significant modulatory effects on the NECS-induced shifts in the concentrations of the studied neuropeptides. Considering the obtained data, a hypothetical scheme of neuropeptide organization of the cerebral NS and ANS has been proposed. In the examined brain structures, there are neuronal populations belonging to the two main neurochemical systems. One of them is SP-ergic, while another consists of mE- and -En-ergic neurons; these systems are in antagonistic relations. Changes in the levels of mE and -En always induce the attended opposite shifts in the SP levels, and vice versa. The lE-ergic neuronal populations, which co-exist with the above neurochemical systems, are relatively nonspecifically activated by either (noci- and antinociceptive) drives, but, according to the pattern of its responses, the lE-ergic system is closer to the SP-ergic one. It is supposed that pain signals, when coming to the vl SGC, activate SP- and lE-ergic neuronal populations; later on, the posterior and lateral hypothalamic nuclei and preoptic region are involved in the transmission of the above signals. When released by the corresponding neuronal populations in the vl SGC, lE activates the key ANS structures (dl SGC and Rd), and the latter, in turn, activate other components of this system, which form its ascending compartment (ventromedial, dorsomedial, and paraventricular hypothalamic nuclei, septum, basolateral amygdala, hippocampal fields 3 and 4, and cingular cortex). In the ANS,-En and mE function as transmitters. 相似文献
20.
W. W. Schwippert T. W. Beneke J. P. Ewert 《Journal of comparative physiology. A, Neuroethology, sensory, neural, and behavioral physiology》1990,167(4):509-520
Summary Intracellular recording and labeling of cells from the toad's (Bufo bufo spinosus) medulla oblongata in response to moving visual (and tactual) stimuli yield the following results. (i) Various response types characterized by extracellular recording in medullary neurons were also identified intracellularly and thus assigned to properties of medullary cell somata. (ii) Focussing on monocular small-field and cyclic bursting properties, somata of such neurons were recorded most frequently in the medial reticular formation and in the branchiomotor column but less often in the lateral reticular formation. (iii) Visual object disrimination established in pretectal/tectal networks is increased in its acuity in 4 types of medullary small-field neurons. The excitatory and inhibitory inputs to these neurons evoked by moving visual objects suggest special convergence likely to increase the filter properties. (iv) Releasing conditions, temporal pattern, and refractoriness of cyclic bursting neurons resemble membrane characteristics of vertebrate and invertebrate neurons known to play a role in premotor/motor activity. (v) Integrating functions of medullary cells have an anatomical correlate in the extensive arborizations of their dendritic trees; 5 morphological types of medullary neurons have been distinguished.Abbreviations
A
stripe moving in antiworm configuration
- (W)
moving in worm configuration
-
S
square
-
BMC
branchiomotor column
-
EPSP
excitatory postsynaptic potential
-
IPSP
inhibitory postsynaptic potential
-
RetF
medullary reticular formation
-
RF
receptive field
-
M neurons
response properties of medullary neurons
-
T neurons
classes of tectal neurons
-
TH neurons
classes of thalamic/pretectal neurons
-
tr.tb.d.
tractus tecto-bulbaris directus
-
tr.tbs.c.
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