共查询到20条相似文献,搜索用时 15 毫秒
1.
The experiment described here tests the effect of intracerebroventricular (icv) injection of nitric oxide (NO) precursors, such as L-arginine (L-arg) and nitroprusside (NP), on the thermogenic changes induced by lesion of the lateral hypothalamus (LH). The firing rate of the nerves innervating interscapular brown adipose tissue (IBAT), along with IBAT and colonic temperatures (TIBAT and TC) were monitored in urethane-anesthetized male Sprague-Dowley rats lesioned in the LH. These variables were measured before and after and icv injection of 4 μmol L-arg or 400 nmol NP. The same variables were also monitored in: a) lesioned rats with icv administration of saline; b) sham-lesioned animals with icv injection of L-arg or NP; c) sham-lesioned rats with icv injection of saline. The results show that L-arg or NP injection reduces the increases in firing rate, TIBAT, and TC induced by LH lesion. These findings suggest that NO plays a key role in the thermogenic changes following LH lesion. 相似文献
2.
The aim of this experiment was to evaluate the effects of an intracerebroventricular (icv) injection of prostaglandin E1 (PGE1) on the sympathetic activation and the thermogenic changes in rats with acute lesions of the ventromedial hypothalamus (VMH). Four groups of six Sprague-Dawley male rats were anesthetized with ethyl-urethane. The firing rate of the sympathetic nerves innervating the interscapular brown adipose tissue (IBAT) and the colonic and IBAT temperatures were monitored both before and after one of the following treatments: 1) VMH lesion plus icv injection of PGE1 (500 ng); 2) VMH lesion plus icv injection of saline; 3) sham lesion plus icv injection of PGE1; and 4) sham lesion plus icv injection of saline. PGE1 induced an increase in the firing rate of IBAT nerves and the colonic and IBAT temperatures. These effects were reduced by VMH lesion. The findings indicate that acute lesions of the VMH reduce the effects of PGE1 and seem to suggest a possible role played by the VMH in the control of the sympathetic activation and the thermogenic changes during PGE1 hyperthermia. 相似文献
3.
Monda M Viggiano A Viggiano A Mondola R Viggiano E Messina G Tafuri D De Luca V 《Peptides》2008,29(1):120-126
Since experiments regarding a possible relation between olanzapine and orexin A has been scarcely reported in international literature, this experiment tested the effect of olanzapine on the sympathetic and thermogenic effects induced by orexin A. The firing rates of the sympathetic nerves to interscapular brown adipose tissue (IBAT), along with IBAT, colonic temperatures and heart rate were monitored in urethane-anesthetized male Sprague-Dawley rats before an injection of orexin A (1.5 nmol) into the lateral cerebral ventricle and over a period of 150 min after the injection. The same variables were monitored in rats with an intraperitoneal administration of olanzapine (10mg/kg bw), injected 30 min before the orexin administration. The results show that orexin A increases the sympathetic firing rate, IBAT, colonic temperatures and heart rate. This increase is blocked by the injection of olanzapine. These findings indicate that olanzapine affects the complex reactions related to activation of orexinergic system. 相似文献
4.
Monda M Viggiano A Viggiano A Viggiano E Messina G Tafuri D De Luca V 《Regulatory peptides》2007,139(1-3):39-44
This experiment tested the effect of a lesion of cerebral catecholaminergic neurons on the sympathetic and thermogenic effects induced by an intracerebroventicular (icv) injection of orexin A. The firing rates of the sympathetic nerves to the interscapular brown adipose tissue (IBAT), along with IBAT, colonic temperatures and heart rate were monitored in urethane-anesthetized male Sprague-Dawley rats before an injection of orexin A (1.5 nmol) into the lateral cerebral ventricle and over a period of 150 min after the injection. Three days before the experiment, the rats were pre-treated with an icv injection of 6-hydroxydopamine (6-OHDA) or 6-OHDA plus desipramine or saline. The results show that orexin A increases the sympathetic firing rate, IBAT, colonic temperatures and heart rate in the rats pre-treated with saline. This increase is blocked by the pre-treatment with 6-OHDA alone or 6-OHDA plus desipramine. These findings indicate that cerebral catecholaminergic neurons (particularly the dopaminergic pathway) play a fundamental role in the complex reactions related to activation of the orexinergic system. 相似文献
5.
Monda M Viggiano A Viggiano A Viggiano E De Luca V 《Physiological research / Academia Scientiarum Bohemoslovaca》2006,55(1):73-78
This experiment tested the effect of risperidone on the sympathetic and thermogenic effects induced by orexin A. The firing rates of sympathetic nerves to interscapular brown adipose tissue (IBAT), along with IBAT and colon temperatures and heart rate were monitored in urethane-anesthetized male Sprague-Dawley rats before an injection of orexin A (1.5 nmol) into the lateral cerebral ventricle and over a period of 2 hours after the injection. The same variables were monitored in rats with an intraperitoneal administration of risperidone (50 mg/kg bw), injected 30 min before the orexin administration. The results show that orexin A increases the sympathetic firing rate, IBAT, colonic temperatures and heart rate. This increase is enhanced by the injection of risperidone. These findings suggest that risperidone elevates the responses due to orexin, probably through an involvement of serotoninergic and dopaminergic pathways, which are affected by risperidone. Furthermore, we suggested the name "hyperthermine A" as additional denomination of "orexin A" by considering the strong influence of this neuropeptide on body temperature. 相似文献
6.
Monda M Viggiano A Viggiano A Fuccio F De Luca V 《Physiological research / Academia Scientiarum Bohemoslovaca》2004,53(5):507-513
This experiment tested the effect of clozapine on the sympathetic and thermogenic effects induced by orexin A. The firing rates of the sympathetic nerves to interscapular brown adipose tissue (IBAT), along with IBAT and colonic temperatures were monitored in urethane-anesthetized male Sprague-Dawley rats before and for 5 h after an injection of orexin A (1.5 nmol) into the lateral cerebral ventricle. The same procedure was carried out in rats treated with orexin A plus an intraperitoneal administration of clozapine (8 mg/kg bw), an atypical antipsychotic that is largely used in the therapy of schizophrenia. The same variables were monitored in rats with clozapine alone. A group of rats with saline injection served as control. The results show that orexin A increases the sympathetic firing rate, IBAT and colonic temperatures. Clozapine blocks completely the reactions due to orexin A. These findings suggest that clozapine influences strongly the thermogenic role of orexin A. Furthermore, the remarkable hyperthermic role played by orexin A is confirmed. 相似文献
7.
The level of γ-aminobutyric acid (GABA) in the posterior hypothalamus, the firing rate of the nerves innervating interscapular brown adipose tissue (IBAT), IBAT and colonic temperatures (TIBAT and Tc) were monitored in urethane-anesthetized male Sprague–Dawley rats. These variables were measured before and after an intracerebroventricular injection of 500 ng prostaglandin E1 (PGE1). The same variables were monitored in other rats with saline injection. The results showed that PGE1 caused an increase in GABA concentration, firing rate, TIBAT, Tc. These findings suggest that GABA-ergic tone in the posterior hypothalamus is important in the control of the sympathetic and thermogenic changes induced by PGE1. 相似文献
8.
《Prostaglandins, Leukotrienes and Medicine》1983,10(1):11-17
Leukotriene C4 (LTC4) and prostaglandin E2 (PGE2) have been studied for their effects on vascular permeability in rats. LTC4 and/or PGE2 were dissolved in 0.3% ethanol and were administered subcutaneously (0.1 ml) in the plantar surface of one of the hind paws of different series of rats. The changes in vascular permeability were measured by the radioactive marker (HSA. I125) method. LTC4 administered in dose of 2 × 10−8M produced marked increase (77 and 133%) in the vascular permeability (local edemogenic effect). PGE2 administered in a dose of 10−6M also produced significant increase (38 and 40%) in the vascular permeability. However, PGE2 in the same dose either administered along with LTC4 or administered at 30 minutes after the injection of LTC4 (2 × 10−8M) did not have any potentiating effect on the edemogenic response of LTC4. 相似文献
9.
Prostaglandin E2 (PGE2) (5 μg in 5 μl) injected into the third ventricle (3rd V) of intact or castrated conscious male rats markedly increased plasma LH titers 15 and 30 min after its injection. PGE1 injected at a similar dose slightly increased plasma LH in intact but not in orchidectomized rats. A small but significant increase in plasma FSH followed 3rd V injection of both PGE2 and PGE1 in intact but not in castrated rats. PGF1α and PGF2α were completely ineffective in modifying plasma LH or FSH titers in either intact or castrated rats. These results indicate that PGE2 and to a lesser extent PGE1 specifically stimulate gonadotropin release in the male rat, possibly by a direct action on the central nervous system. They also support the hypothesis that PGE2 and perhaps PGE1 play a physiological role in neural control of pituitary gonadotropin release. 相似文献
10.
PROSTAGLANDINS of the E type (PGE1, PGE2) inhibit sympathetic neurotransmission in several tissues and species1–4. On the basis of their natural occurrence and availability for release, as well as observations on the pharmacological actions of the PGs, endogenous PGE1 and PGE2 are postulated to operate on sympathetic neurotransmission by a feedback mechanism and thereby modulate the effector responses to nerve activity1, 5. Inhibition by 5,8,11,14-eicosatetraynoic acid (ETA) of PG synthesis in the cat spleen and in the rabbit heart increases the release of noradrenaline (NA) in response to nerve stimulation, thus strongly supporting the hypothesis6, 7. We report here that guinea-pig vas deferens releases PG in response to nerve stimulation and that the neuromuscular transmission is facilitated after inhibition of PG synthesis. PG synthesis was irreversibly inhibited using ETA8. 相似文献
11.
T. Esposito An. Viggiano Al. Viggiano E. Viggiano A. Giovane B. Varriale G. Messina V. De Luca M. Monda 《Journal of thermal biology》2006
This experiment evaluated the induction of RNA synthesis in neurons of various cerebral areas during hyperthermia induced by an intracerebroventricular injection of orexin A. The firing rates of the sympathetic nerves to interscapular brown adipose tissue, along with interscapular brown adipose tissue and colon temperatures, and heart rate were monitored in urethane-anesthetized male Sprague–Dawley rats before and after an injection of orexin A (1.5 nmol) into the lateral cerebral ventricle. Furthermore, the incorporation of 3H-uridine in total RNA and the expression of mRNA encoding the precursor of orexin A were measured in the cerebral areas at the 4th hour after the injection. The same variables were monitored in control rats with an injection of saline. The results show that orexin A increases the sympathetic firing rate, interscapular brown adipose tissue and colonic temperatures, heart rate, along with: (1) the incorporation of 3H-uridine in total RNA of the hypothalamus, hippocampus, cortex and cerebellum, (2) the expression of mRNA encoding the precursor of orexin A in the hypothalamus, cortex and cerebellum. These findings indicate that orexin A induces polyhedral gene expressions in several cerebral regions. Furthermore, we insist to suggest the name “hyperthermine A” as an additional denomination of “orexin A” by considering the strong influence of this neuropeptide on body temperature. 相似文献
12.
Interactions of prostaglandin E1 (PGE1) with morphine have been reported in several test systems and an hypothesis has been advanced for a role of prostaglandins in morphine analgesia and physical dependence. In rats self-administering morphine intravenously, a simultaneous and continuous infusion of naloxone hydrochloride at 56 to 560 μg/kg/day caused the expected increase in injection rate for morphine. Infusion of PGE1 by itself at 56 or 180 μg/kg/day had no effect on the rate of morphine intake. Likewise the addition of PGE1 at 180 μg/kg/day did not potentiate the increase caused by naloxone (56 or 180 μg/kg/day) when it was added to the naloxone infusion. These results do not support a role for prostaglandins in the behavioral aspects of morphine addiction. However, larger doses of PGE1 (1 and 1.8 mg/kg/day), which were without overt effects in normal rats, caused severe and incapacitating prostration in morphinized rats. 相似文献
13.
Three behavioral tests, spontaneous locomotor activity (SLMA), exploratory behavior (EB) and rotarod performance (RP), a measure of neuromuscular coordination, were used to study the interaction of PGE1 (1 mg/kg i.p., 10 min. pretreatment) with DBcAMP (25 mg/kg i.p., 25 min. pretreatment) in mice. A dose-response relationship of PGE1 (0.01–5.0 mg/kg) to SLMA was determined, with a significant decrease in SLMA produced by a dose of 0.1 mg/kg. Decreases in SLMA were produced by PGE1 (79%), DBcAMP (41%) and DBcAMP-PGE1 combination (71%). Similar decreases in EB were observed. Although no significant difference between controls and DBcAMP was observed in RP, 52% of mice tested were RP failures following PGE1 and a 100% failure rate was induced by the combination. Mice were treated with a second injection of DBcAMP or PGE1 or the combination 24 hr following the first injection. Behavioral activity of these mice was observed 25 min (DBcAMP) or 10 min (PGE1) after the second dose was administered. A second injection of DBcAMP failed to decrease SLMA and EB from controls; moreover, SLMA began to return towards control levels as early as 2 hr between injections. The second injection of PGE1 or DBcAMP+PGE1 produced the same behavior as that produced by the first injection. On the basis of these results, the relationship of cyclic nucleotides and PGs to behavioral activity is discussed. 相似文献
14.
Infusion of prostaglandin E1 (PGE1) into the renal artery of anesthetized dogs (1.03 μg/min) caused increases in urine flow rate (V), renal plasma flow (RPF) and renin secretion rate without any change in mean arterial blood pressure (MABP), whereas infusion of prostaglandin F2α (PGF2α), (1.03 μg/min) caused no consistent change in V, RPF, or renin secretion rate. Infusion of prostaglandin E2 (PGE2) (1.03 μg/min) into the renal artery of “non-filtering” kidneys caused renin secretion rate to rise from 567.7 ± 152.0 U/min(M ± SEM) during control periods to 1373.6 ± 358.5 U/min after 60 minutes of infusion of PGE2 (P < 0.01), without significant change in MABP (P > 0.1). The data suggest that PGE1 and PGE2 play a role in the control of renin secretion. The data further suggest that PGE may control renin secretion through a direct effect on renin-secreting granular cells. 相似文献
15.
Role of Phosphate and Kinetic Characteristics of Complete Iron Release from Native Pig Spleen Ferritin-Fe 总被引:4,自引:0,他引:4
He-Qing Huang Qing-Mei Lin Bo Kong Run-Ying Zeng Yu-Huan Qiao Can-He Chen Feng-Zhang Zhang Liang-Shu Xu 《Journal of Protein Chemistry》1999,18(4):497-504
The kinetics for complete iron release showing biphasic behavior from pig spleen ferritin-Fe (PSFF) was measured by spectrophotometry. The native core within the PSFF shell consisted of 1682 hydroxide Fe3+ and 13 phosphate molecules. Inhibition kinetics for complete iron release was measure by differential spectrophotometry in the presence of phosphate; the process was clearly divided into two phases involving a first-order reaction at an increasing rate of 46.5 Fe3+/PSFF/min on the surface of the iron core and a zero-order reaction at a decreasing rate of 6.67 Fe3+/PSFF/min inside the core. The kinetic equation [C(PSFF-Fe3+)max – C(PSFF-Fe3+)
t
]1/2 = T
max –T
t gives the transition time between the two rates and represents the complex kinetic characteristics. The rate was directly accelerated twofold by a mixed reducer of dithionite and ascorbic acid. These results suggest that the channel of the PSFF shell may carry out multiple functions for iron metabolism and storage and that the phosphate strongly affects the rate of iron release. 相似文献
16.
F.M. Lai T.K. Tanikella H. Herzlinger C. Shepherd P. Cervoni 《Prostaglandins & other lipid mediators》1984,27(2):273-284
The effect of CL 115,347, a topically active antihypertensive PGE2 analog, and PGE2 on changes in blood pressure (BP), heart rate (HR) response and plasma epinephrine (E) and norepinephrine (NE) levels induced by stimulation of the sympathetic spinal cord outflow were studied in pithed stroke-prone spontaneously hypertensive rats (SHRSP). Surgical pithing significantly reduced plasma E but not NE levels suggesting that the sympathoadrenal medullary system differentially affects E and NE release. Sympathetic stimulation of the spinal cord of pithed SHRSP increased HR, BP, plasma E and NE levels. Topically applied CL 115,347 (0.001–0.1 mg/kg) dose-dependently decreased BP, while intravenously infused PGE2 (30 μg/kg/min) did not alter BP except for a brief initial drop. Topical application of CL 115,347 (0.1 mg/kg) also inhibited BP responses to sympathetic stimulation without effects on HR or plasma E or NE levels. Intravenous infusion of PGE2 (30 μg/kg/min) inhibited both BP and HR responses to spinal cord stimulation but did not alter plasma catecholamine levels. These studies in SHRSP suggest that CL 115,347 and PGE2 modulate cardiovascular responses mainly via postjunctional effects, but act differently on the cardiovascular elements,
CL 115,347 acts primarily on blood vessels while PGE2 acts on blood vessels and heart. 相似文献
17.
Marianne Wennmalm Garret A. FitzGerald ke Wennmalm 《Prostaglandins & other lipid mediators》1987,33(5)
Prostaglandin E2 (PGE2) has previously been shown to inhibit sympathetic neurotransmission in different organs and species. Based on this inhibitory effect and on its reversal by cyclo-oxygenase inhibitors, PGE2 has been claimed to be a physiological modulator of in vivo release of norepinephrine (NE) from sympathetic nerves. It is now recognized that prostacyclin (PGI2) is the main cyclo-oxygenase product in the heart. We therefore addressed the question whether PGI2, within the same preparation, is formed in increased amounts during sympathetic nerve stimulation and has neuromodulatory activity.The effluent from isolated rabbit hearts subjected to sympathetic nerve stimulation or to infusion of NE or adenosine (ADO) was collected, and its content of PGE2 and 6-keto-PGF1α (dehydration product of PGI2) was analyzed using gas chromatography/mass spectrometry, operated in the negative ion/chemical ionization mode. Other hearts were infused with PGI2 and nerve stimulation induced outflow of endogenous NE into the effluent was analyzed using HPLC with electrochemical detection. Nerve stimulation at 5 or 10 Hz (before but not after adrenergic receptor blockade), as well as infusion of NE (10−6–10−5M) or ADO (10−4M) increased the cardiac outflow of 6-keto-PGF1α. Basal and nerve stimulation induced efflux of 6-keto-PGF1α was approximately 5 times higher than the corresponding efflux of PGE2. PGI2 dose-dependently inhibited the outflow of NE from sympathetically stimulated hearts, the inhibition at 10−6M being approximately 40%.On the basis of these observations we propose that PGI2 is a more likely candidate than PGE2 as a potential modulator of neurotransmission in cardiac tissue in vivo. 相似文献
18.
In rats receiving high doses of estrogen along with progesterone, the uterus is desensitized and does not respond to artificial stimuli with increased endometrial vascular permeability or decidualization. In addition, prostaglandin E2 (PGE2), the putative mediator of endometrial vascular permeability changes in sensitized uteri, is ineffective when given into the uterine lumen. The possibility that this inability of PGE2 to increase endometrial vascular permeability may be related to the unavailability of hitamine of bradykinin was investigated. Rats were differentially sensitized for the decidual cell reaction by the daily injection of 2 mg progesterone with either 0.5 of 10 μg estrone for the 3 days preceding the unilateral intra-uterine injection of 50 μl phosphate buffered saline containing gelatin with or without 10 μg PGE2 and with or without 1 mg histamine or 1 μg bradykinin. Prior to the intrauterine injection, all rats were treated with indomethacin to inhibit endogenous prostaglandin production. Endometrial vascular permeability changes were determined 8 h later by determining radioactivity levels in injected and non-injected uterine horns 15 min after the i.v. injection of 125I-labelled bovine serum albumin. PGE2 increased endometrial vascular permeability in rats receiving 0.5 μg estrone, but not in those receiving 10 μg. Histamine or bradykinin, alone or with PGE2, did not affect endometrial vascular permeability in rats receiving either estrogen dose. The data suggest that the unresponsiveness of uteri from rats treated with high doses of estrogen is not simply due to the unavailability of bradykinin or histamine. 相似文献
19.
《Journal of thermal biology》2004,29(1):21-29
The purpose of this study was to investigate the effect of active pre-warming combined with three regimens of fluid ingestion: (1) fluid replacement equal to sweat rate (FF), (2) fluid replacement equal to half the sweat rate (HF), and (3) no fluid replacement (NF). Eight males cycled to voluntary fatigue at 70% of peak power output (PPO) in 31.3±0.4°C, 63.3±1.2% relative humidity in a randomised fashion in either of FF, HF or NF conditions. For each trial the time to fatigue test was preceded by 2×20 min active pre-warming periods where subjects also cycled at 70% PPO. Subjects commenced each exercise period with identical rectal temperatures (Tre). The rate of increase in Tre for each condition during the first 20 min of active pre-warming was not different. However, the rate of increase in Tre was significantly reduced in the second active pre-warming period for all fluid conditions but no differences between conditions were noted. During the fatigue test, the rate of increase in Tre for FF was 0.29°C h−1 and 0.58°C h−1 for HF but were not significantly different. The rate of increase in Tre for the NF trial was 0.92°C h−1 and was significantly higher compared to the FF trial. Overall mean skin temperatures and mean body temperatures were higher for NF compared to FF and HF. The rate of heat storage during the fatigue test was similar for FF (80.1±11.7 W m−2) and HF (73.0±13.7 W m−2) conditions but increased to 155.8±31.2 W m−2 (P<0.05) in the NF trial. The results indicate that fluid ingestion equal to sweat rate has no added benefit over fluid ingestion equal to half the sweat rate in determining time to fatigue over 40 min of sub-maximal exercise in warm humid conditions. Fluid restriction accelerates the rate of increase in Tre after 40 min of exercise, thereby reducing the time to fatigue. The data support the model that anticipation of impending thermal limits reduces efferent command to working skeletal muscle ensuring cellular preservation. 相似文献
20.
Jean W. T. Smolders Rainer Klinke 《Journal of comparative physiology. A, Neuroethology, sensory, neural, and behavioral physiology》1984,155(1):19-30
Summary The effect of temperature on the response properties of primary auditory fibres in caiman was studied. The head temperature was varied over the range of 10–35 ° C while the body was kept at a standard temperature of 27 °C (Ts). The temperature effects observed on auditory afferents were fully reversible. Below 11 °C the neural firing ceased.The mean spontaneous firing rate increased nearly linearly with temperature. The slopes in different fibres ranged from 0.2–3.5 imp s–1 °C–1. A bimodal distribution of mean spontaneous firing rate was found (<20 imp s–1 and >20 imp s–1 at Ts) at all temperatures.The frequency-intensity response area of the primary fibres shifted uniformly with temperature. The characteristic frequency (CF) increased nearly linearly with temperature. The slopes in different fibres ranged from 3–90 Hz °C–1. Expressed in octaves the CF-change varied in each fibre from about O.14oct °C–1 at 15 °C to about 0.06 oct °C–1 at 30 °C, irrespective of the fibre's CF at Ts. Thresholds were lowest near Ts. Below Ts the thresholds decreased on average by 2dB°C–1, above Ts the thresholds rose rapidly with temperature. The sharpness of tuning (Q10db) showed no major change in the temperature range tested.Comparison of these findings with those from other lower vertebrates and from mammals shows that only mammalian auditory afferents do not shift their CF with temperature, suggesting that a fundamental difference in mammalian and submammalian tuning mechanisms exists. This does not necessarily imply that there is a single unifying tuning mechanism for all mammals and another one for non-mammals.Abbreviations
BF
best frequency: frequency of maximal response at an intensity 10 dB above the CF-threshold
-
CF
characteristic frequency
-
FTC
frequency threshold curve, tuning curve
-
T
s
standard temperature of 27 °C 相似文献