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1.
We studied the effects of a neuroprotector, riluzole, on the evoked mass activity of spinal neuronal mechanisms and on action
potentials (APs) recorded from the sciatic nerve in intact rats and rats with the manifestations of postdenervational and
4-aminopyridine (4-AP)-induced hyperreflexia, as well as in animals in the superreflexia state (induced by combined action
of denervation and 4-AP). We measured the parameters of monosynaptic reflex discharges (monosynaptic reflexes, MRs) recorded
from the ventral root (VR), of the spinal dorsal surface potential (DSPs), and of mass APs evoked in afferent and efferent
fibers of the SN before and 10, 30, 60, and 120 min after injection of riluzole. It was found that in intact animals riluzole
significantly (by 60–70%) decreased the amplitude of VR MRs and those of the afferent peak and N1 component of DSPs. Riluzole exerted smaller suppressive effects on mass APs in the afferent fibers of the SN; the effect
on APs in the SN efferent fibers was the minimum (a 4 to 5% decrease). Under conditions of increased sensitivity of the motoneuronal
postsynaptic membrane to the transmitter (postdenervational hyperreflexia) and an increased release of glutamate from presynaptic
elements (4-AP-induced hyperreflexia), as well as under superreflexia conditions, the dynamics of suppression of the evoked
spinal activity by riluzole showed relatively moderate differences from those in intact animals. Under the above conditions,
riluzole in the same manner decreased the amplitude of VR MRs. In the superreflexia state, the agent blocked the development
of additional components of these dramatically increased potentials (in the above state, their amplitude increased by nearly
nine times, on average, and this resulted in the generation of such components). We believe that the inhibitory effect of
riluzole on glutamatergic neurotransmission in the spinal cord is based, first of all, on blocking of excitation in afferent
presynaptic terminals. The possibility to use riluzole for correction of abnormally increased hyperexcitability of the spinal
neuronal systems is discussed.
Neirofiziologiya/Neurophysiology, Vol. 37, Nos. 5/6, pp. 416–423, September–December, 2005. 相似文献
2.
We studied monosynaptic reflex discharges (MRD) recorded from the ventral roots (VR) of rats subjected to systemic administration
with thyroliberin, thyroxin, or 4-aminopyridine (4-AP). Under such conditions, in some of the experiments the MRD amplitude
reached values sufficient to excite non-active VR fibers. In these cases, immediately after the MRD peak had been reached,
abnormally increased responses (AIR) developed, whose amplitude was 2–2.5 times higher than the amplitude of highly facilitated
MRD. Proofs are presented that AIR reflect excitation of “neighboring” VR fibers, which were not involved in the reflex response,
and MRD plays the role of a “stimulus” exciting these fibers. Therefore, we demonstrate the possibility of transmission of
excitation from “active” to “silent” fibers within a nerve trunk under conditions of the development of “superreflexia”. This
state can be considered a model of excitation spreading via a non-synaptic pathway under conditions of hyperexcitability of
the CNS structures, in seizure states in particular.
neirofiziologiya/Neurophysiology, Vol. 32, No. 2, pp. 120–127, March–April, 2000. 相似文献
3.
The spinal superreflexia state was modeled in experiments on rats using preliminary transection of the spinal cord and injection
(in the course of the acute experiment) of 4-aminopyridine. An extremely high (reaching 15–20 mV) amplitude of monosynaptic
reflex discharges (MRs) evoked by stimulation of the dorsal root and recorded from the ventral root (VR) L
4 and the presence of an additional component in the above discharges were phenomena indicative of the development of the above
state. Under such conditions, the amplitudes of the discharges evoked in the VR by electrical stimulation of the round window
of the labyrinth (vestibular stimulation) and of the discharges elicited by stimulation of the motor cortex under conditions
of bilateral transection of the pyramids increased several times. Thresholds of the VR responses to vestibular and cortical
stimulations demonstrated an about threefold drop; latencies of the mass responses and responses of single spinal moto-and
interneurons decreased about twofold, on average. The pattern of vestibular conditioning effects on the VR MRs changed: in
intact animals vestibular stimulation induced inhibition of the VR MRs, while in animals with superreflexia such stimulation
led to facilitation of the MRs. Cortical stimulation under conditions of pyramidotomy in both intact animals and animals with
superreflexia resulted in facilitation of the VR MRs of a nearly the same intensity. The levels of convergence of the segmental
and supraspinal effects on interneurons and motoneurons of the rat spinal cord dramatically increased under superreflexia
conditions. The possible mechanisms of augmentation of the descending influences on spinal neuronal systems under the above
conditions are discussed.
Neirofiziologiya/Neurophysiology, Vol. 38, No. 2, pp. 140–149, March–April, 2006. 相似文献
4.
In experiments on rats, we studied 4-aminopyridine (4-AP)-induced modifications of the excitability of peripheral nerve fibers in an efferent trunk, the ventral root (VR), and in a mixed trunk including both afferent and efferent fibers, the sciatic nerve (SN). For this purpose, we examined how 4-AP influenced the parameters of integral action potentials recorded from the VR and SN in three experimental modes. These were: (i) stimulation of the SN and recording of antidromic action potentials from the VR in vivo after systemic injections of 4-AP into the animal, (ii) stimulation of a preparation of the SN dissected from the animal after systemic injection of 4-AP and recording of action potentials from another segment of the same preparation in vitro, and (iii) stimulation of an SN preparation and recording of action potentials from another region of this preparation in vitro, but after direct application of the solution of 4-AP to this preparation. It was found that 4-AP significantly increased the threshold for generation of action potentials and enhanced their amplitude, decreased the duration of action potentials recorded from the VR, and shortened the refractory period following these responses. The drug also significantly increased the amplitude and decreased the duration of action potentials recorded from the SN in vitro after systemic injections of the agent, but the threshold for response generation in this preparation noticeably dropped; the post-response refractory period in this case showed no changes. Modifications of action potentials recorded from the SN in vitro after direct applications of 4-AP were in general similar to the described above. Other examined parameters of action potentials (chronaxia and dynamics of an increase in the amplitude related to intensification of stimulation) showed no significant changes under the influence of 4-AP. We conclude that 4-AP increases the excitability of nerve fibers in the nerve trunks under study, but not to the point where the electrical interaction between excited and nonexcited fibers in the fiber conductors under study (VR and SN) overcomes the threshold. 相似文献
5.
In experiments on rats, we studied the characteristics of reflex discharges in the ventral root (VR) L
5; the discharges were evoked by stimulation of segmental (peripheral nerve or dorsal root, DR) and suprasegmental vestibular
(stimulation of the round window of the labyrinth) inputs. Potentials were recorded within different time intervals (from
1 to 150 days) after transection of the sciatic nerve (SN); measures preventing regeneration of its fibers were used. Modifications
of the segmental responses related to post-denervational changes included four phases: (i) latent period, (ii) post-denervational
spinal hyperreflexia (PDSH), (iii) partial suppression of monosynaptic discharges (MDs) in the VR, and (iv) complete disappearance
of VR MDs resulting from late post-denervational changes. The latency of post-denervational modifications was about 18–48
h after the moment of transection of the SN. Within the PDSH phase, modifications were the greatest 3 to 5 days after transection;
these changes could be more adequately estimated in the case of stimulation of the DR on the side of transection and not under
conditions of stimulation of the central segment of the transected SN per se. Within this phase, the amplitudes of VR MDs and responses to vestibular stimulation were augmented two to three and four
to five times, as compared with the respective indices in intact animals. From the 7th to 10th day after the nerve transection,
the amplitude of VR MDs progressively dropped, and on about the 20th day these discharges practically disappeared, while polysynaptic
components of segmental responses were preserved. Vestibular responses within this period were, as earlier, considerably facilitated.
On the 60th and 150th days (within the phase of late post-denervational modifications) there were no VR MDs after stimulation
of segmental inputs, and polysynaptic responses were exclusively observed. The amplitude of discharges evoked by vestibular
stimulation became lower than in the PDSH state but remained significantly higher than the control values of this parameter.
Probable mechanisms of post-denervational modifications of the evoked spinal activity within different time intervals after
transection of the SN are discussed.
Neirofiziologiya/Neurophysiology, Vol. 39, No. 1, pp. 37–46, January–February, 2007. 相似文献
6.
Apoptotic cells in the taste buds of mouse circumvallate papillae after the sectioning of bilateral glossopharyngeal nerves
were examined by the method of DNA nick-end labeling (TUNEL), together with standard electron microscopy. The taste buds decreased
in number and size 3–11 days after denervation and disappeared at 11 days. The TUNEL method revealed only a few positively
stained nuclei in normal taste buds but, in those of mice 1–5 days after denervation, the number of positive nuclei had increased
to 3–5 times that of taste buds from normal mice. Electron-microscopic observation after denervation demonstrated taste bud
cells containing condensed and fragmentary nuclei in a cytoplasm with increased density. The results show that taste bud cells
under normal conditions die by apoptosis at the end of their life span, and that gustatory nerve sectioning causes apoptosis
of taste bud cells with taste buds decreasing in number and ultimately disappearing.
Received: 20 November 1995 / Accepted: 15 May 1996 相似文献
7.
Excitatory and inhibitory neurotransmission in the central nervous system can be modulated by neurosteroids. We previously
found that in rat hippocampal slices allopregnanolone (3α-hydroxy-5α-pregnan-20-one), a positive GABAA receptor modulator, suppresses the epileptic discharges induced by 4-aminopyridine (4-AP), a convulsant K+ channel blocker that stimulates glutamate release. Here, we tested the action of allopregnanolone on the epileptogenic and
excitotoxic effects of the intrahippocampal administration of 4-AP in vivo. Drugs were perfused by a microdialysis cannula-electrode
in the dorsal hippocampus and the EEG was recorded. Extracellular levels of aspartate, glutamate and GABA were analyzed by
HPLC in the microdialysis fractions, and 24 h after the experiment the hippocampus was studied histologically. 4-AP induced
intense epileptic discharges, increased the extracellular levels of aspartate, glutamate, and GABA by 383, 420, and 245%,
respectively, and produced a notable neurodegeneration in CA1 and CA3 areas. Allopregnanolone administration alone did not
affect the electrical activity, amino acids levels or cellular morphology, but when co-infused with 4-AP incremented 55–77%
the duration of the epileptic discharges, and potentiated 32–49% the release of glutamate in comparison with 4-AP alone. The
4-AP-induced neurodegeneration was not modified by allopregnanolone. The NMDA receptor antagonist MK-801 protected against
the epilepsy and neurodegeneration produced by 4-AP, and allopregnanolone did not affect this protection. We conclude that,
differently from the observations in vitro, allopregnanolone potentiated the stimulatory effect of 4-AP on glutamate release
and that this may explain the potentiation of the epileptogenic effect of 4-AP in vivo. 相似文献
8.
Nagayama T Seiryu M Deguchi T Kano M Suzuki T Takano-Yamamoto T Ichikawa H 《Cellular and molecular neurobiology》2012,32(3):391-397
The distribution of calcitonin gene-related peptide (CGRP) was examined in the periodontal ligament (PDL) after experimental
luxation injury of the rat first molar tooth. The luxational injury increased the number of CGRP-immunoreactive (IR) nerve
fibers. At 3–7 days, numerous CGRP-IR nerve fibers appeared throughout the injured PDL. These nerve fibers terminated as free
nerve endings within resorption cavities. Immunohistochemistry for receptor activity modifying protein 1 (RAMP1) also demonstrated
that the subunit of CGRP receptor was expressed by periodontal cells adjacent to the alveolar bone in the intact and injured
PDL. RAMP1-IR cells were divided into two types; small cells with single nucleus and large cells with 2–6 nuclei. After the
luxational injury, both types of RAMP1-IR cells abundantly appeared within resorption cavities. As a result, the treatment
increased the number of large RAMP1-IR cells at 3–7 days and small RAMP1-IR cells at 7 days. In addition, a double immunofluorescence
analysis demonstrated that CGRP-IR nerve fibers were seen away from RAMP1-IR cells in the intact PDL. After the traumatic
injury, however, CGRP-IR nerve fibers appeared in the close vicinity of small and large RAMP1-IR cells at 5–7 days. The morphology
and distribution of RAMP1-IR cells suggest that they contain osteoblasts and osteoclasts. By affecting osteoclasts and osteoblasts,
CGRP may have effects on bone remodeling in the luxated PDL. 相似文献
9.
Membrane potentials, cable parameters, and component resting ionic conductances of gastrocnemius fibers from normal goats were measured in vitro at six to 32 days following denervation by section of the tibial nerve. Denervated fibers were depolarized an average of 11.6 +/- 1.5 mV (six preparations) from the control mean of 62.1 +/- 1.0 mV (124 fibers) over the period studied. Fibrillation, tetrodotoxin-resistant action potentials, and anode-break excitation were present in the denervated preparations after 13 days. The control cable parameters from 124 fibers (13 preparations) were membrane resistance, 1052 +/- 70 omega-cm2 and membrane capacitance, 6.2 muF/cm2. In denervated fibers membrane resistance increased two to three times in the 13 to 32 day period; membrane capacitance increased about 50% in normal solution at eight to nine, 27-28, and 32 days. Myoplasmic resistivity was assumed to be 112 omega-cm. Measurements were made at 38 degrees C. Component resting conductances were determined from the cable parameters in normal and chloride-free solution. Mean chloride conducantance GC1 and mean potassium conductance GK of control fibers were 776 +/- 49 mumhos/cm2 and 175 +/- 15 mumhos/cm2 (92 fibers), respectively. Following denervation GC1 increased slightly at six to nine days then fell to low values at 16 to 32 days that were close to or indistinguishable from zero. GK increased significantly to 372 +/- 40 mumhos/cm2 and 499 +/- 90 mumhos/cm2 at 16 to 20 and 32 days, respectively. It was concluded from these findings that GC1 and GK of mammalian skeletal muscle are controlled by factors from the nerve and/or muscle action potentials. Goat muscle is different from frog muscle in which GC1 does not change and GK decreases during denervation. 相似文献
10.
Changes in the antioxidative enzyme activities (SOD, CuZnSOD, GSH-Px, GST), as well as TBARS content in 5-week-old tomato
(Lycopersicon
esculentum Mill. cv “Perkoz”) roots were examined 1, 3 h (short-term stress) and 1–14 days (long-term stress) after a single application
of 50 mM (mild stress) and 150 mM NaCl (severe stress). The severe stress caused an increase in GST, GSH-Px and SODs activities
from the beginning of the experiment while mild stress induced enhancement of GST activity from the second day of experiment.
The maximum increase in SODs after both NaCl solutions were applied and in GST activity after the higher NaCl dose on the
second day of the experiment was observed. Moreover, after 1 h of NaCl treatment with both tested NaCl solutions, the highest
induction of GSH-Px activity appeared. TBARS content was elevated from the first hour of salt stress and decreased only 14 days
after 50 mM NaCl application which was accompanied by high induction of GSH-Px activity. In conclusion, enhanced activities
of tested enzymes indicate their involvement in early and late defence systems under salinity stress. Moreover, the dynamics
of the changes in the antioxidant enzymes suggests that the second day following NaCl application is a crucial moment of the
experiment with regard to salt-mediated oxidative stress. 相似文献
11.
Navegantes LC Resano NM Baviera AM Migliorini RH Kettelhut IC 《American journal of physiology. Endocrinology and metabolism》2004,286(4):E642-E647
Rates of protein synthesis were investigated in skeletal muscles from rats submitted to chemical and surgical sympathectomy. Three models of sympathetic denervation were used: 1) treatment with guanethidine (100 mg.kg(-1).day(-1) sc); 2) lumbar sympathetic denervation (surgical excision of the second and third lumbar ganglia of the sympathetic chain, from which arises the postganglionic fibers to the skeletal muscles of rat hindlimb); and 3) adrenodemedullation. Protein synthesis was estimated in isolated soleus muscle by the rate of incorporation of [(14)C]tyrosine (0.1 mM, 0.05 microCi/ml) into total protein. Soleus isolated after 2 and 4 days of chemical sympathectomy or after 3 days of lumbar denervation showed a 17-20% statistically significant decrease in in vitro rates of protein synthesis. These effects were reverted by addition of 10(-5) M isoproterenol or epinephrine in vitro. Neither clenbuterol nor isoproterenol (10(-7), 10(-6), or 10(-5) M) in vitro affected the rate of protein synthesis in soleus from normal rats. On the other hand, clenbuterol or epinephrine (10(-5) M) increased by 20% the rate of protein synthesis in soleus muscles from adrenodemedullated rats and prevented its decrease in muscles from fasted rats. The data suggest that the sympathetic nervous system stimulates protein synthesis in oxidative muscles, probably through the activation of beta(2)-adrenoceptors, especially in situations of hormonal or nutritional deficiency. 相似文献
12.
Excitability parameters of m. digastricus muscle fibers were investigated in anesthetized (40 mg/kg of nembutal) rats 3-5 days after denervation. The number of fibers with high polarization level was increased as was the number of fibers with low and medium level in both bellies of m. digastricus. The differences in the level of polarization recorded in the muscle fibers of the abdominoposterior m. digastricus disappeared after denervation. It is suggested that denervation syndrome in m. digastricus deprived of spindle receptors was similar to that observed in other skeletal muscles. 相似文献
13.
J. Morel F. Rannou H. Talarmin M. A. Giroux-Metges J. P. Pennec G. Dorange G. Gueret 《The Journal of membrane biology》2010,235(2):109-119
This study analyzes changes in the distribution, electrophysiological properties, and proteic composition of voltage-gated
sodium channels (NaV) in cultured adult rat skeletal muscle fibers. Patch clamp and molecular biology techniques were carried out in flexor digitorum
brevis (FDB) adult rat skeletal muscle fibers maintained in vitro after cell dissociation with collagenase. After 4 days of
culture, an increase of the NaV1.5 channel type was observed. This was confirmed by an increase in TTX-resistant channels and by Western blot test. These
channels exhibited increased activation time constant (τm) and reduced conductance, similar to what has been observed in denervated muscles in vivo, where the density of NaV1.5 was increasing progressively after denervation. By real-time polymerase chain reaction, we found that the expression of
β subunits was also modified, but only after 7 days of culture: increase in β1 without β4 modifications. β1 subunit is known to induce a negative shift of the inactivation curve, thus reducing current amplitude and duration. At day
7, τh was back to normal and τm still increased, in agreement with a decrease in sodium current and conductance at day 4 and normalization at day 7. Our
model is a useful tool to study the effects of denervation in adult muscle fibers in vitro and the expression of sodium channels.
Our data evidenced an increase in NaV1.5 channels and the involvement of β subunits in the regulation of sodium current and fiber excitability. 相似文献
14.
Summary The neuropeptide content of nerve fibers associated with submucosal arteries in the small intestine of guinea pigs was studied in whole-mount preparations using immunohistochemical methods. Tissues were obtained from normal animals or animals in which the small intestine had been extrinsically denervated. In normal animals, submucosal arteries are innervated by extrinsic sensory nerve fibers which contain both substance P and calcitonin gene-related peptide, and by sympathetic noradrenergic nerve fibers. In preparations obtained from animals 5–9 days after denervation, nerve fibers which contained substance P without detectable calcitonin gene-related peptide were associated with a few submucosal arteries. Nerve fibers which contained vasoactive intestinal peptide were also associated with some arteries. By 42–48 days after extrinsic denervation, substance P-containing fibers (without calcitonin gene-related peptide) and vasoactive intestinal peptide-containing fibers were associated with nearly every blood vessel. The extrinsic sympathetic nerve fibers did not regenerate during the course of this study. The nerve fibers associated with submucosal arteries in denervated tissues were not sensitive to capsaicin treatment.The alteration in the innervation of submucosal arterioles that follows extrinsic denervation of the gut may reflect either an increase in the neuropeptide content of the fibers, synthesis of a new peptide, or an increase in the number of fibers as a result of axonal sprouting. 相似文献
15.
Summary An efficient system to regenerate shoots on excised sepals (calyx) of greenhouse-grown ‘Bounty’ strawberry (Fragaria x ananassa Duch.) was developed in vitro. Sepal cultures produced multiple buds and shoots without an intermediary callus phase on 2–4 μM 1-phenyl-3-(1,2,3-thiadiazol-5-yl) urea (thidiazuron, TDZ)-containing shoot induction medium within 4–5 wk of culture initiation.
Young expanding sepals with the adaxial side touching the culture medium and maintained for 14 d in darkness produced the
best results. In a second experiment, sepals proved more effective than the leaf discs and petiole segments for regenerating
shoots. A third experiment compared the effects of six concentrations of two cytokinins (TDZ at 0, 0.5, 2, and 4 μM and zeatin at 2 and 4 μM) for elongation of sepal-derived adventitious shoots. The media containing TDZ generally promoted more callus formation and
suppressed shoot elongation. TDZ-initiated cultures transferred into the medium containing 2–4 μM zeatin, produced usable shoots after one additional subculture. Shoots were rooted in vitro in the same medium used for shoot regeneration, but without any growth regulators. When transferred to potting medium, 85–90%
of in vitro plantlets survived. 相似文献
16.
The direct shoot organogenesis was achieved from leaf explant of two commercially important clones of Populus deltoides on MS medium enriched with 15 mg/l adenine sulphate, 5 mg/l Ascorbic acid, 250 mg/l (NH4)2SO4 (referred to as PD1 medium) supplemented with 2.5 µM each of 6-benzylaminopurine and indole-3-acetic acid. Higher shoot organogenic potential was recorded from the explants of clone ‘G48’ as compared to clone ‘L34’. The age of leaf explant also affected the shoot organogenic potential, and maximum shoot organogenesis was recorded in case of 5th leaf from the top of microshoot. Histological studies revealed altered cell division resulting in the formation of meristematic pockets after 5 days of culture, these meristematic pockets grew into dome protuberances by 10th day. Organized shoots were visible after 15 days of culture. A clear three phases of shoot organogenesis viz induction (0–4 days), initiation and organization (4–10 days) and growth (11–16 days onwards) were observed. Marked variation in the activity of enzymes such as catalase, peroxidase, polyphenol oxidase and acid phosphatase was observed during these phases. The activity of these enzymes was found to increase in cultures grown on the medium resulting in shoot organogenesis during shoot development (after 7 days of culture). 相似文献
17.
In Wistar albino rats with experimental hyperthyroidism (HTh) and control animals, we measured parameters of the responses evoked in peripheral segments of the ventral and dorsal roots (VR and DR, respectively) by stimulation of the sciatic nerve. We found that the chronaxia of the afferent fibers of the sciatic nerve in HTh animals is shorter, while the duration of the mass action potential (AP) in the DR is somewhat longer than in the control. Under conditions of HTh, the excitation threshold of the efferent fibers became higher, the chronaxia decreased, and the second high-amplitude component could appear in the AP recorded from the VR. Possible mechanisms of changes in the excitability of afferent and efferent fibers of the sciatic nerve and specific features of the AP recorded from the VR under HTh conditions are discussed. In particular, we consider the possibility of ephaptic spreading of excitation in VR fibers under HTh conditions. 相似文献
18.
Shukuwa K Izumi S Hishikawa Y Ejima K Inoue S Muramatsu M Ouchi Y Kitaoka T Koji T 《Histochemistry and cell biology》2006,126(1):111-123
Diethylstilbestrol (DES) has been implicated in mammalian abnormalities. We examined the effects of DES on follicle-stimulating hormone (FSH), luteinizing hormone (LH), and prolactin (PRL) cells in the pituitaries of male mice treated with various doses of DES for 20 days. DES reduced the density of FSH and LH cells in a dose-dependent manner, but increased that of PRL cells. When the expression of estrogen receptor (ER) α and β was assessed, an induction of ERβ by DES was found predominantly in PRL cells. However, since these effects were abolished in ERα knockout mice, DES appears to act primarily through ERα. When the expression of Ki-67 and Pit-1 in PRL cells was examined at various time-points after DES treatment, some PRL cells became Ki-67 positive at 10–15 days, and Pit-1-positive cells were increased at 5–15 days. Furthermore, some FSH and LH cells became Pit-1 positive, and co-localized with PRL at 5–10 days. Our results indicate that DES increases PRL cells by inducing proliferation of PRL cells and transdifferentiation of FSH/LH cells to PRL cells. 相似文献
19.
Acetylcholine Receptors : Revised Estimates of Extrajunctional Receptor Density in Denervated Rat Diaphragm 总被引:11,自引:1,他引:10
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Douglas M. Fambrough 《The Journal of general physiology》1974,64(4):468-472
The number of extrajunctional acetylcholine receptors (125I-labeled α-bungarotoxin binding sites) per unit length of muscle fiber and the average fiber circumference were determined for rat diaphragm muscle fibers denervated 0, 2, 4, 7, 10, and 14 days. From these data receptor densities (sites per square micrometer of surface) were calculated. Values thus obtained were considerably lower than those estimated previously by autoradiography. Receptor density increased from < 6 sites/µm2 in innervated muscle to 635 ± 29 sites/µm2 14 days after denervation. The form of the relationship between receptor density and acetylcholine sensitivity and the time-course of change in receptor density after denervation are as previously reported. 相似文献
20.
Specific features of thermoregulation behavior were studied, and values of the selected and final selected temperature (25.1°C)
for early juveniles of roach Rutilus rutilus aged 11–28 days after hatching were first studied in long-term experiments (16 days). Two periods of the process of thermoselection—transient
(selected temperature, up to 7–9 days after the beginning of the experiment) and final (final selected temperature, 8–10 days
after the beginning of the experiment)—have been identified. The selection by larval roach of final selected temperature values
occurs with use of the adaptation response of “excessive responding.” It was shown that correct determination of final selected
temperature values for early juveniles of fish is possible only in long-term experiments (more than 7 days). The obtained
results can be used during the analysis of behavior and distribution of larval roach under natural and experimental conditions. 相似文献