共查询到20条相似文献,搜索用时 15 毫秒
1.
F. Chaouloff V. Baudrie D. Laude 《Naunyn-Schmiedeberg's archives of pharmacology》1990,341(4):381-384
Summary 8-Hydroxy-2-(di-n-propylamino)tetralin (8OH-DPAT) is a 5-HT1A receptor-selective agonist that has recently been reported to trigger adrenal catecholamine release and hyperglycemia. The aim of this study was to analyze in the conscious rat whether the 5-HT1A receptor subtype is involved in these effects.8-OH-DPAT (0.1–1 mg/kg, i.v.) evoked dose-dependent increases in plasma adrenaline and glucose concentrations. Increases in plasma adrenaline levels peaked 5 min after administration of 8-OH-DPAT; in contrast, plasma glucose levels rose throughout the 20 min period of analysis. Prior administration of (–)pindolol, a beta-adrenoceptor antagonist that blocks 5-HT1A receptors, markedly diminished the rise in plasma adrenaline levels and abolished the hyperglycemia triggered by 8-OHD-PAT. On the other hand, neither the selective beta 1-adrenoceptor antagonist, betaxolol, the selective beta 2-adrenoceptor antagonist, ICI 118.551, nor the 5-HT2 receptor antagonist, ketanserin, affected 8-OH-DPAT-induced increases in plasma adrenaline levels. In addition, except for ICI 118.551 pretreatment, which delayed the hyperglycemic effect of 8-OH-DPAT, none of these antagonists affected the rise in glycaemia evoked by 8-OHD-PAT.The data suggest that the adrenaline-releasing and a major part of the hyperglycemic effects of 8-OH-DPAT are mediated by activation of 5-HT1A receptors.
Send offprint requests to F. Chaouloff at the above address 相似文献
2.
Circadian rhythm in the behavioral responsiveness to the selective 5-HT1A receptor agonist 8-hydroxy-2-(di-n-propylamino)tetralin (8-OH-DPAT) was studied in rats. Rats were subcutaneously injected with 8-OH-DPAT at one of the following times of day: 0000, 0400, 0800, 1200, 1600, 2000 hours. The postsynaptic 5-HT1A receptor behavioral syndrome, that is, forepaw treading, head weaving, and flat body posture, were measured after the administration of 8-OH-DPAT. Circadian rhythms were found in each of the behavioral responses to 8-OH-DPAT. Peak responses were observed in the mid-dark phase (1200 hours) while the weakest responses were observed in the midlight phase (0000 hours). In a subsequent experiment, 8-OH-DPAT was administered intracerebroventricularly during the mid-dark phase and the mid-light phase. The behavioral responses to the drug in the middark phase were significantly higher than those in the mid-light phase. These results suggest that the function of central postsynaptic 5-HT1A receptor exhibits circadian rhythm. 相似文献
3.
H. O. Kalkman 《Psychopharmacology》1990,101(1):39-42
The role of 5-HT1A autoreceptors in the discriminative stimulus properties of 8-OH-DPAT (0.1 mg/kg, SC) in rats, was investigated. Drug lever appropriate responding to 8-OH-DPAT (0.1 mg/kg, SC) and ipsapirone (3 mg/kg, SC) was measured before and after treatment with para-chlorophenylalanine (pCPA) at a dose (150 mg/kg IP, –3 and –2 days) which causes severe depletion of brain 5-HT stores. The recognition of the drug stimulus was not significantly altered by pCPA. These results indicate that activation of 5-HT1A autoreceptors is of minimal importance to the 8-OH-DPAT cue. 相似文献
4.
In the rat shock-induced ultrasonic vocalization test, the anxiolytic effects of the 5-HT1A receptor agonist 8-hydroxy-2-(di-n-propylamino)tetralin (8-OH-DPAT) obtained after systemic (IP) and intracerebral injection into the dorsal raphe nucleus (DRN) were selectively abolished by pretreatment with the 5-HT1A receptor antagonist WAY-100635 [N-[2-[4-(2-methoxyphenyl)-1-piperazinyl]ethyl]-N-(2-pyridinyl) cyclo-hexanecarboxamide trihydrochloride]. This blockade was demonstrated both after systemic and DRN application of WAY-100635. Therefore, it is concluded that the anxiolytic effects of 8-OH-DPAT are mediated by activation of somatodendritic 5-HT1A receptors. 相似文献
5.
Rationale and objectives Serotonin (5-hydroxytryptamine, 5-HT) is widely distributed in the central nervous system and it is well established that this neurotransmitter plays an inhibitory role in the control of ingestive behavior. Administration of various 5-HT agonists and selective serotonin reuptake inhibitors, including fluoxetine (FLU), suppress food intake under free-feeding and food-restricted conditions. In contrast, activation of somatodendritc 5-HT1A receptors in the raphe nuclei reduces forebrain 5-HT bioavailability and agonists of these receptors, including 8-hydroxy-2-(di-n-propylamino)tetralin (8-OH-DPAT), reliably stimulate eating behavior.Methods In the present study male (n=8 per group) and female (n=8 per group) rats were pretreated with 8-OH-DPAT in an attempt to reverse FLUs inhibitory effect on feeding. 8-OH-DPAT was injected into either the dorsal or median raphe of male and female rats at doses of 0.1–0.4 nmol. FLU was then injected IP at a dose of 2 mg/kg. Both compounds were administered just prior to the onset of the dark cycle. Food intake was measured 2 h post-injection. Similar effects were also measured in female rats after ovariectomy.Results and conclusions FLU suppressed food intake comparably in male and female rats. Dorsal and median raphe injections of 8-OH-DPAT dose dependently reversed the anorectic effect of FLU in male rats. Higher doses of 8-OH-DPAT completely antagonized this response. In female rats, however, 8-OH-DPAT pretreatment was largely ineffective except in ovariectomized females where results were similar to male rats. These findings suggest that male and female rats are differentially sensitive to the ability of 5-HT1A receptor agonists to antagonize the feeding suppressive action of FLU and imply a role for neuroendocrine mechanisms in enabling the somatodendritic autoreceptor to control serotonergic neurotransmission under these conditions. 相似文献
6.
Alfredo Briones-Aranda Mariano Castillo-Salazar 《Pharmacology, biochemistry, and behavior》2009,92(1):182-189
Stress is closely related with levels of corticosteroid and corticotrophin releasing factor, which at the same time can modify 5-HT1A receptors and brain serotonin levels. Consequently, the absence of corticosteroids in rats induced by an adrenalectomy could be useful to understand the functionality of the brain serotonergic system after a stressing event.The influence of 15 min of forced swimming was explored on sham and adrenalectomized rats by measuring the 5-HT1A receptor density in raphe and hippocampus. Other previously stressed groups (sham and adrenalectomized) were tested in two anxiety models with the 5-HT1A agonist 8-OH-DPAT, the postsynaptic antagonist MM-77, and with a combination of these two compounds.It was found that the removal of adrenals in rats that were not previously stressed induced an increase in the postsynaptic 5-HT1A receptor density. On the other hand, an adrenalectomy in rats that were previously stressed induced a reduction in the same receptor density. Adrenal gland removal induced an anxiolytic-like effect. However, after the injection of 8-OH-DPAT, adrenalectomized rats showed anxiogenic-like actions, an effect which was reversed by MM-77.Data show that changes in 5-HT1A receptors density caused by a stressful session can have behavioral consequences, thus emphasizing the need to reconsider the clinical use of 5-HT1A ligands after traumatic events. 相似文献
7.
Ryozo Oishi Yoshinori Roh Kiyomi Saeki 《Naunyn-Schmiedeberg's archives of pharmacology》1992,345(5):495-499
Summary The effects of 5-hydroxytryptamine (5-HT) receptor agonists on histamine turnover in mouse and rat brains were examined. The histamine turnover rate was estimated from the accumulation of tele-methylhistamine 90 min after i.p. injection of pargyline (65 mg/kg). In whole mouse brains, the histamine turnover was significantly inhibited by the 5-HT1A agonists, 8-hydroxy-2(di-n-propylamino)tetralin (8-OH-DPAT) (> 0.5 mg/kg) and buspirone (> 2 mg/kg) injected s. c. 10 min before pargyline treatment. 5-hydroxytryptophan (20 mg/kg) also significantly inhibited histamine turnover. Injections of the 5-HT1B agonist m-trifluoromethylphenylpiperazine (10 and 20 mg/kg) or the 5-HT2 agonist (1-(2,5-dimethoxy-4-iodophenyl)-2-aminopropane (1, 2 and 5 mg/kg)), however, did not affect histamine turnover. The inhibitory effect of 8-OH-DPAT (1 mg/kg) on histamine turnover was significantly antagonized (by 40%) by pindolol (20 mg/kg) and slightly antagonized (by 29%) by spiperone (10 mg/kg), while methysergide (20 mg/kg) and ketanserin (10 mg/kg) demonstrated no antagonistic effects. 8-OH-DPAT (0.3 and 1 mg/kg) also showed an inhibiting effect on histamine turnover in various regions of rat brains. Although the extent of inhibition was slightly larger in the striatum and cerebral cortex, there was no marked regional difference. These results suggest that histaminergic activity in the brain is regulated by 5-HT1A receptors.
Send offprint requests to R. Oishi at the above address 相似文献
8.
Previously it has been shown that 5-hydroxytryptamine (5-HT)1A agonists such as 8-hydroxy-2-(di-n-propylamino)tetralin (8-OH-DPAT) and gepirone increase food intake in free-feeding rats. These experiments were conducted to examine the possible influence of taste and textural factors on the feeding responses induced by these two drugs. Separate groups of non-water-deprived rats were given access to one of a variety of different solutions of saccharin (0.02, 0.04, 0.20 and 2.0% w/v) or water for 2 h each day. Rats were then treated with different doses of 8-OH-DPAT (10, 60 or 100 µg/kg) or gepirone (1 or 2.5 mg/kg) in a repeated measures design. Under saline injection an inverted-U shaped concentration-response curve was obtained, with the highest level of intake occurring in rats drinking from the 0.20% saccharin solution. The highest doses of 8-OH-DPAT and gepirone suppressed drinking of saccharin, particularly over the first 30 min of the test period, leading to a flattening of the concentration response curve. At 2 h post-injection 60 µg/kg 8-OH-DPAT enhanced the consumption of the 0.04% saccharin solution only. In a second experiment, 8-OH-DPAT or gepirone was administered to rats eating either standard pelleted chow or the same food presented in powdered form. Both drugs stimulated feeding. However, interactions with food type were found. At 60 and 100 µg/kg 8-OH-DPAT increased eating of both food types equally, but with 500 µg/kg rats are significantly more of the pelleted food. Gepirone at 1 and 2.5 mg/kg also significantly increased pelleted food intake compared to powdered food intake. These results suggest that taste factors alone are unlikely to be a major determinant of 8-OH-DPAT's effects on food intake. On the other hand, food texture may play a significant role in the capacity to elicit feeding after high doses of both 8-OH-DPAT and gepirone. 相似文献
9.
The present study evaluated the role of various neurotransmitter systems in mediating buspirone's blockade of the fear-potentiated startle effect, where acoustic startle amplitude is normally increased in the presence of a light previously paired with a shock. Large lesions of the dorsal and median raphe nuclei or IP injections of the serotonin antagonists cinanserin (10 mg/kg) or cyproheptadine (5 mg/kg) did not alter fear-potentiated startle, nor did these treatments prevent buspirone (5 or 10 mg/kg SC) from blocking fear-potentiated startle. The 5-HT1A agonist 8-OH-DPAT (2.5–10.0) did not block fear-potentiated startle even at doses that produced a marked 5-HT syndrome. Another 5-HT1A agonist, ipsapirone (10–20 mg/kg), blocked potentiated startle only at a very high dose (40 mg/kg).p-Chlorophenylalanine andp-chloroamphetamine did not alter fear-potentiated startle. Finally, pretreatment with the benzodiazepine receptor antagonist RO-15-1788 (1 mg/kg); the opiate antagonist naloxone (2 mg/kg) or the 2-adrenergic antagonist yohimbine (5 mg/kg) did not reduce fear-potentiated startle, nor did they prevent buspirone from blocking fear-potentiated startle. Taken together, the data do not support the hypothesis that buspirone's anxiolytic effects are mediated by actions at 5-HT1A receptors and more generally indicate that serotonergic neurons do not play an important role in fear-potentiated startle. 相似文献
10.
The effects of antimanic agents, including lithium, carbamazepine, clonazepam and zotepine, on the postsynaptic 5-HT1A receptor-mediated behavioral and hypothermic responses induced by 8-OH-DPAT in rats, and on [3H]8-OH-DPAT binding to 5-HT1A receptors in the rat hippocampus were examined. Treatment with lithium (3 mEq/kg, IP) for 14 days enhanced forepaw treading, one component of the 5-HT behavioral syndrome induced by 8-OH-DPAT, and this enhancement by lithium was abolished by catecholamine depletion with reserpine or -methyl-p-tyrosine, but not by 5-HT depletion withp-chlorophenylalanine. These data suggest that lithium enhances 5-HT1A-mediated behavior via catecholaminergic systems. In contrast, chronic lithium treatment did not alter the hypothermic response to 8-OH-DPAT in untreated rats, as well as in rats treated with reserpine. These findings strengthen the suggestion that lithium has no direct influence on the postsynaptic 5-HT1A-mediated response. Other antimanic agents had no effect on either forepaw treading or hypothermia induced by 8-OH-DPAT. Radioligand binding studies using [3H]-8-OH-DPAT demonstrated that chronic lithium treatment, but not other antimanic agents, caused 5-HT1A receptor down-regulation in rat hippocampus. A discrepancy therefore exists between 5-HT1A receptor down-regulation and unaltered 5-HT1A-mediated behavioral and hypothermic responses in catecholamine-depleted rats after chronic lithium treatment. 相似文献
11.
Recent studies have suggested that anxiety may be an important factor in the non-opioid analgesic response to defeat in muroid rodents. In the present study, we have examined the influence of the 5-HT1A receptor agonist, 8-OH-DPAT, oin basal nociception and defeat analgesia in male DBA/2 mice. Our results show that, while devoid of intrinsic activity on the mouse tail-flick assay, 8-OH-DPAT blocks the analgetic consequences of defeat. A ten-fold potency differential was observed as a function of route of injection, with minimum effective doses of 0.1 and 1.0 mg/kg for subcutaneous and intraperitoneal administration, respectively. Although further studies are required, these preliminary data support 5-HT1A receptor involvement in the mediation of this form of adaptive pain inhibition. 相似文献
12.
Effects of water deprivation and restraint were compared in the rat elevated X-maze. Water deprivation for 12–48 h increased corticosterone and had a duration-dependent anxiolytic effect in the elevated X-maze, increasing the ratio of open/total arm entries (OTR) and the proportion of time spent on the open arms (% time) without affecting total entries. Brain 5HIAA/5HT was increased only after 24 or 48 h deprivation. Restraint for 15 min also increased plasma corticosterone and brain 5HIAA/5HT but had no effect on behaviour in the elevated X-maze when rats were tested immediately afterwards. However, 1 h restraint was anxiogenic in the elevated X-maze immediately after release, reducing OTR and % time, but with a less consistent reduction in total entries; reductions in OTR and % time were still present 24 h later. The 5HT1A agonist 8-hydroxy-2-(di-n-propylamino) tetralin (8-OH-DPAT) (0.1–0.2 mg/kg), administered 10 min before testing in the elevated X-maze, had anxiogenic actions in non-stressed rats. The effect of 0.1 mg/kg 8-OH-DPAT was not significantly altered by 24 or 48 h water deprivation but was abolished by restraint for 1 h immediately beforehand, despite the anxiogenic effect of restraint alone. Similar mutual antagonism of 8-OH-DPAT and restraint occurred when the dose of 8-OH-DPAT was increased to 0.2 mg/kg. Twenty-four hours after restraint, restrained rats which had received 8-OH-DPAT (0.1–0.2 mg/kg) still did not show any significant anxiogenic effect compared with non-restrained vehicle treated controls. Restraint-induced deficits in elevated X-maze exploration may prove a useful model with which to study the pharmacology of depression-related anxiety. However, the effects of the stressors examined, and their interaction with 8-OH-DPAT in the elevated X-maze, appear to depend on the nature of the stressor. 相似文献
13.
Rats were trained to self-administer cocaine (0.5 mg/kg/infusion) and were then pretreated with the 5-HT1A agonist 8-OH-DPAT (0.125, 0.25 or 0.5 mg/kg, SC). 8-OH-DPAT pretreatment produced a decrease in reinforced response rates. When the effect of 8-OH-DPAT (0.5 mg/kg, SC) on responding for a range of cocaine doses was assessed, the drug produced a decrease in response rates when lower doses of cocaine served as the reinforcer. Fluoxetine (10 mg/kg, IV), an indirect 5-HT agonist, also reduced reinforced response rates for a low dose infusion of cocaine. Rates of responding for infusions of higher cocaine doses were not affected by fluoxetine pretreatment during an FR1 schedule of reinforcement. When an FR10 schedule of reinforcement was imposed, reinforced response rates for infusions of higher doses of cocaine were also reduced. Thus, under conditions that produce high rates of responding (low dose infusion or high ratio requirements for an infusion) fluoxetine reduced responding. This effect may be due to the effects at the 5-HT1A receptor, since 8-OH-DPAT produced a similar effect on cocaine self-administration. Given that the effects of these 5-HT agonists are observed only when low doses of cocaine serve as the reinforcer or when task demands are high, it is possible that the suppression of responding reflects an effect that is not specific to the reinforcing impact of cocaine. An alternative explanation for these effects incorporates a concept of unit cost/cocaine infusion that allows for direct comparison across studies that employ different reinforcement schedules. 相似文献
14.
This study examined whether the antidepressant-like effect of serotonin (5-HT)1A receptor agonists in the forced swim test (FST) is mediated by 5-HT1A receptors. The 5-HT1A receptor agonists 8-hydroxy-2-(di-n-propylamino) tetralin (8-OH-DPAT) and buspirone decreased immobility in the FST. The effect of 8-OH-DPAT was blocked by the 5-HT1A receptor antagonists NAN 190, BMY 7378 and pindolol. The effect of buspirone was blocked by NAN 190 and pindolol. The antagonists produced no effects on their own. The norepinephrine (NE) uptake inhibitor desipramine (DMI) also reduced immobility, and this was also blocked by NAN 190, BMY 7378 and pindolol. The
1,
1 and
2 adrenergic antagonists prazosin, betaxolol and ICI 118,551 did not block either 8-OH-DPAT or DMI, and produced no effects on their own. These results provide evidence that the antidepressant-like effects of 5-HT1A receptor agonists in the FST are mediated through 5-HT1A receptors, probably located postsynaptically. The finding that the 5-HT1A receptor antagonists blocked the effect of DMI suggests that the NE and 5-HT systems interact in the FST. 相似文献
15.
We studied the effects of the 5-HT(1A/7) agonist 8-OH-DPAT on haloperidol-induced catalepsy and forebrain Fos expression in mice to clarify its mechanism in modulating extrapyramidal motor disorders. 8-OH-DPAT (0.1-1mg/kg, i.p.) markedly attenuated haloperidol-induced catalepsy in a dose-dependent manner with a potency greater than that of the antiparkinsonian agent trihexyphenidyl. The anticataleptic action of 8-OH-DPAT was completely antagonized by WAY-100135 (a selective 5-HT(1A) antagonist), but not by SB-269970 (a selective 5-HT(7) antagonist). Depletion of cerebral 5-HT by p-chlorophenylalanine (300mg/kg, i.p. for 3 days) did not attenuate, but rather potentiated the action of 8-OH-DPAT. Furthermore, the anticataleptic dose of 8-OH-DPAT showed a regionally specific reduction of haloperidol-induced Fos expression in the dorsolateral striatum (dlST) and the core region of the nucleus accumbens (AcC), without affecting that in the medial prefrontal cortex, the shell region of the nucleus accumbens or the lateral septal nucleus. These results suggest that 8-OH-DPAT alleviates antipsychotic-associated extrapyramidal motor disorders by stimulating the postsynaptic 5-HT(1A) receptors, which specifically counteracts the D(2) receptor blocking actions of antipsychotics in the dlST and AcC. 相似文献
16.
Previous studies have shown that discriminative stimulus control established with the 5HT1A receptor agonist, 8-OH-DPAT, generalises to other 5HT1A agonists and partial agonists but also to the 2-adrenoceptor antagonist, yohimbine. On the basis of these results it has been proposed that the 8-OH-DPAT cue may be produced by activity at more than one receptor. In the present study rats were trained to discriminate a dose of 8-OH-DPAT (0.05 mg/kg, SC) from saline. Substitution tests showed dose-dependent generalisation with the 5HT1A compounds, buspirone, ipsapirone, MDL 72832 and MDL 73005EF, the 2-adrenoceptor antagonists, yohimbine and idazoxan, and BMY 14802, which is usually described as a sigma ligand. The buspirone metabolite 1-pyrimidinyl piperazine (1-PP) which possesses mainly 2-adrenoceptor antagonist properties produced only partial generalisation which was not dose related. Receptor binding studies showed that all the compounds which substituted for 8-OH-DPAT displaced [3H]-8-OH-DPAT binding to rat hippocampal membranes. Furthermore, there were statistically significant positive correlations between drug affinity for 5HT1A sites and their ED50 values for both substitution for 8-OH-DPAT and potency to decrease response rates. These results are consistent with the view that the 8-OH-DPAT cue, like the ability of the compounds tested to decrease rates of responding, is largely mediated by activity at 5HT1A receptors. 相似文献
17.
J. E. Barrett S. M. Hoffmann S. N. Olmstead M. J. Foust C. Harrod B. A. Weissman 《Psychopharmacology》1989,97(3):319-325
The effects of spiroxatrine, a putative antagonist with selectivity for the serotonin (5-HT)1A receptor, were compared with compounds believed to function as agonists at the 5-HT1A receptor. Schedule-controlled responding of pigeons was maintained under a multiple 30-response fixed-ratio (FR), 3-min fixed-interval (FI) schedule or under a schedule in which responding was suppressed by electric shock (conflict procedure). Under the multiple schedule, spiroxatrine (0.3–1.0 mg/kg) decreased FR responding but did not affect FI responding; responding was decreased in both schedule components at 3.0 mg/kg. When administered alone, buspirone, a compound believed to produce its anxiolytic effects through 5-HT1A agonist actions, produced effects similar to those of spiroxatrine; in combination, the two drugs produced greater effects than when either was administered alone. As with 5-HT1A agonists such as buspirone and 8-hydroxy-2(di-n-propylamino)tetralin (8-OH-DPAT) in the pigeon, spiroxatrine (0.01–1.0 mg/kg) increased punished responding. Spiroxatrine and buspirone were potent inhibitors of [3H]8-OH-DPAT binding to pigeon cerebral membranes with IC50 values in the nM range. Neurochemical analyses of metabolite changes produced by spiroxatrine in pigeon cerebrospinal fluid showed buspirone-like effects, with increases in MHPG, DOPAC and HVA at doses that decreased 5-HIAA levels. Spiroxatrine dose-dependently blocked the behavioral effects of the dopamine agonist piribedil indicating that, like buspirone, it also is a potent dopamine antagonist. Spiroxatrine most likely functions as an agonist at the 5-HT1A receptor. As with buspirone, however, spiroxatrine has a prominent dopamine antagonist component. 相似文献
18.
Rationale The contribution of the 5-HT1A somato-dendritic autoreceptor populations to spontaneous and cocaine-induced locomotion is unclear.Objectives To use a low dose range of ±8-hydroxy-2-(di-n-propylamino)tetralin (8-OHDPAT) to preferentially stimulate 5-HT1A autoreceptors and a medium 8-OHDPAT dose range to stimulate both 5-HT1A autoreceptors and postsynaptic receptors as pretreatments prior to either saline or cocaine.Methods In experiment 1, either a medium dose of 8-OHDPAT (0.4 mg/kg) or a low dose (0.05 mg/kg) was given as pretreatments 20 min before five separate 20-min open-field tests. In experiment 2, the pretreatments were changed to a low dose range of 8-OHDPAT (0.01–0.05 mg/kg), with or without WAY 100635 (0.01–0.05 mg/kg). In experiment 3, the 8-OHDPAT pretreatments (0.01, 0.025 or 0.05 mg/kg) were administered 20 min prior to saline or cocaine (10 mg/kg) tests. In experiment 4, a medium dose range (0.2–0.3 mg/kg) was given 20 min prior to saline or cocaine (10 mg/kg) tests.Results Experiment 1 showed that 8-OHDPAT (0.4 mg/kg) tended to increase locomotor activity but that pretreatment with 0.05 mg/kg severely suppressed locomotor activity. In experiment 2, 8-OHDPAT in the low dose range inhibited locomotor activity and this effect was reversed by co-administration of WAY 100635. Experiment 3 showed that the low-dose 8-OHDPAT pretreatment reduced locomotor activity in saline but not cocaine tests. In experiment 4, 8-OHDPAT in the medium dose range enhanced locomotor activity in cocaine tests.Conclusions It is suggested that the facilitatory effect of 8-OHDPAT on cocaine-induced locomotor stimulation is mediated by inhibition of 5-HT1A somato-dendritic autoreceptors. 相似文献
19.
Robert J. Blanchard Jon K. Shepherd Janna Armstrong Sheri F. Tsuda D. Caroline Blanchard 《Psychopharmacology》1993,112(1):55-65
Several behaviors associated with the serotonin syndrome have been reported in rats following administration of the 5-HT1A receptor agonist 8-OH-DPAT. The present investigation approached this phenomenon from an ethopharmacological perspective, and provided a detailed temporal analysis of the behavioral effects of this compound over a 2-h period, in both male and female rats in the home cage. In addition, in order to further characterize the nature of the forepaw-treading and locomotor elements, and assess the extent of influence of the physical characteristics of the test arena, this study provided a detailed analysis of these behaviors in both the home cage and a large oval runway. In the initial analysis, the data indicate a distinct chronological sequence of effects following 8-OH-DPAT treatment. For example, flat back activity and lower lip retraction were apparent within a few minutes post-injection, the former dissipating after about 30 min and being replaced as the prepotent response by a more general (curved back) locomotor enhancement, while the latter effect remained throughout the 2-h test period. Interestingly, there were reliable gender differences in terms of the onset and disappearance of several behavioral components, with females generally being more rapidly affected, but recovering earlier than males. The detailed analysis of locomotor activity and forepaw treading would suggest that the locomotor syndrome primarily involves forward movement, heavily guided by the physical environment. Furthermore, forepaw-treading would seem only to occur when an animal reaches a barrier and forward movement is briefly interrupted, as no reliable incidence of this behavior was observed in the open area of the test area. Together, these findings provide further characterization of the behavioral syndrome induced by 8-OH-DPAT, and indicate the importance of time post-administration, gender of the subject, and the physical characteristics of the test environment, when considering stereotypical drug effects.Supported by NIH Grant MH42803 and RCMI Grant RR03061 相似文献
20.
J.-P. Voigt H. Fink C. A. Marsden 《Naunyn-Schmiedeberg's archives of pharmacology》1995,351(3):217-220
The present study was designed to examine possible interactions between exogenous CCK and the 5-HT1A receptor subtype mediated serotonergic effects on feeding in rats. The somatodendritic 5-HT1A receptor agonist 8-OH-DPAT (0.32 mg/kg sc) evoked feeding in freely feeding rats. This effect was attenuated by treatment with CCK-8 (1, 5 and 25 g/kg ip). In food deprived rats, CCK-8 (40 g/kg ip) significantly reduced the size of a test meal. Treatment with the 5-HT1A receptor antagonist WAY-100135 (10 mg/kg ip) antagonized this anorectic effect of CCK-8. WAY-100135 on its own did not affect food intake. These results suggest the involvement of the 5-HT1A receptor subtype in mediating 5-HT-CCK interactions in the control of food intake in rats. 相似文献