Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0020672 (hypothermia)
 17,327 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

1 The central alpha-adrenoceptors responsible for mediating clonidine-induced sedation in rats have been characterized according to their sensitivity to alpha-adrenoceptor agonists and antagonists.2 Clonidine, injected intraperitoneally or intracerebroventricularly, caused dose-dependent sedation, both in terms of a reduction in the time that rats could remain on an accelerating rotarod and in terms of overt sedation assessed visually. Following intracerebroventricular injection, xylazine, naphazoline and methoxamine, but not phenylephrine, produced similar effects.3 The sedation caused by intraperitoneal injection of clonidine was antagonized by intracerebroventricularly injected phentolamine, yohimbine, piperoxan and tolazoline but not by labetalol, thymoxamine or prazosin.4 The relative potencies of the agonists in causing sedation and of the antagonists in inhibiting the sedative effect of clonidine clearly demonstrated that the central alpha-adrenoceptors mediating clonidine-induced sedation are the same as the peripheral presynaptic alpha(2)-adrenoceptors.5 All the alpha-adrenoceptor agonists caused hypothermia after intracerebroventricular injection, but their order of potency was different from that in producing sedation. The hypothermic effect of intraperitoneally injected clonidine was little affected by any of the antagonists administered intracerebroventricularly. No conclusions could be drawn concerning the type of receptor responsible for mediating hypothermia.
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PMID:Alpha 2-adrenoceptors mediate clonidine-induced sedation in the rat. 4 Jun 43

1. Previous work from our laboratory has shown that cannabis induces aggressive behaviour in rats that have been deprived of rapid eye movement (REM) sleep. It was suggested that this effect was related to brain catecholamines, with dopamine playing an agonist role and noradrenaline an inhibitory one. The present paper describes new experiments dealing with this subject. 2. Previous REM sleep-deprivation enhanced both delta9-tetrahydrocannabinol (THC)-induced hypothermia and nomifensine effects on aggressive behaviour. 3. A marihuana extract decreased brain dopamine turnover in REM sleep-deprived rats, an effect not observed in non-deprived rats. Noradrenaline metabolism was not altered. 4. Fighting behaviour was elicited in REM sleep-deprived rats treated with 4 different dopamine-beta-hydroxylase inhibitors. 5. Apomorphine, nomifensine and delta9-THC administered to non-deprived rats pretreated with bis(4-methyl-1-homopiperanzinyl-thiocarbonyl) disulphide (Fla-63), induced fighting behaviour. 6. Nomifensine and apomorphine induced fighting in non-deprived rats pretreated with delta9-THC. 7. Clonidine inhibited the fighting elicited in REM sleep-deprived rats by either delta9-THC or Fla-63 pretreatment. 8. The data are discussed in terms of the influence of REM sleep-deprivation (or the stress associated with deprivation) on the response to dopaminergic drugs and cannabis. Taken together they emphasize the participation of brain dopamine and noradrenaline systems in the aggressive behaviour studied.
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PMID:Cannabis, catecholamines, rapid eye movement sleep and aggressive behaviour. 20 20

Effects of clonidine on blood pressure, heart rate and rectal temperature in conscious rats were examined. Clonidine (0.1-1 mg/kg s.c.) caused a prevailing pressor response and dose-dependently a fall in heart rate and body temperature. The pressor response to clonidine (0.3 mg/kg s.c.) was completely reduced by phentolamine (10 mg/kg s.c.), chlorpromazine (10 mg/kg s.c.) but not by hexamethonium (30 mg/kg i.p.), guanethidine (30 mg/kg s.c.) or reserpine (5 mg/kg s.c. 18 hr + mg/kg i.p. 4 hr prior to clonidine). Conversely, a remarkable potentiation of the pressor response to clonidine was observed after treatment with reserpine. The bradycardia with clonidine (0.3 mg/kg s.c.) was significanlty reduced by phentolamine, chlorpromazine or atropine (5 mg/kg s.c.) but was potentiated by reserpine. The hypothermia with clonidine (0.3 mg/kg s.c.) was not influenced by phentolamine or atropine but was significanlty potentiated by chlorpromazine. From the above results it is suggested that the prevailing pressor response to clonidine in conscious rats is due to a stimulation of peripheral alpha-adrenoceptors, the bradycardia with clonidine is exerted through the sympathetic pathway and the baroceptor-vagal reflex, and that the hypothermia with clonidine is mainly due to the central mechanism.
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PMID:Effect of clonidine on blood pressure, heart rate and body temperature in conscious rats. 86 83

Shapiro's syndrome comprises agenesis of the corpus callosum in association with episodic hyperhidrosis and hypothermia. We describe a 25-year-old man who is the twentieth case to be reported. There was no evidence of epilepsy, sympathetic nervous system dysfunction or inappropriate vasopressin release. However, investigation demonstrated a central defect in temperature regulation with an abnormally low hypothalamic set-point and normal homeothermic reflexes. Therapy with clonidine, an alpha 2-adrenoceptor agonist, was associated with remission of symptoms: these recurred on four occasions when clonidine was withdrawn. Clonidine therapy was also associated with a return to normal central temperature regulation. We suggest that the efficacy of clonidine reflects an action on hypothalamic thermoregulation rather than on peripheral catecholamine release. These findings have implications for the use of clonidine in other patients with Shapiro's syndrome and in more common disorders of temperature control, including perimenopausal flushing.
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PMID:Clonidine therapy for Shapiro's syndrome. 163 Dec 58

Clonidine may be a source of serious toxicity when ingested by toddlers. We describe 11 cases of clonidine ingestion by toddlers (mean dose 0.15 mg/kg; range 0.01 to 0.57). The source of the clonidine was a grand-parent in six of 11 cases. Symptoms included altered level of consciousness (n = 11), miosis (n = 5), bradycardia (n = 8), hypotension (n = 5), apnea and respiratory depression (n = 6), hypothermia (n = 5) and hypertension (n = 3). Therapeutic interventions included naloxone (n = 8) and atropine (n = 4), dopamine (n = 1), fluid resuscitation (n = 4), and endotracheal intubation (n = 1). There were no deaths. Symptoms of clonidine ingestion were typically mild if the dose ingested was less than 0.01 mg/kg, while bradycardia and hypotension occurred usually with doses of greater than 0.01 mg/kg. Apnea and respiratory depression were common when the dose exceeded 0.02 mg/kg. More effective measures are needed to prevent these potentially serious intoxications.
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PMID:Critical care for clonidine poisoning in toddlers. 220 40

The central action of oxaprotiline (OXA) enantiomers, administered in a single dose, was studied in rats and mice. (+)-OXA and (-)-OXA attenuated reserpine- and apomorphine-induced hypothermia [(+)-OXA in a more potent manner] in mice and reduced the immobility time in the behavioural despair test in rats. Both OXA enantiomers inhibited locomotor activity in mice and rats, and enhanced and prolonged amphetamine- and apomorphine-induced stereotypy in rats. (-)-OXA potentiated the amphetamine hyperactivity in rats, but not in mice. Nomifensine hyperactivity in rats was unaffected by either enantiomer, and locomotor hypoactivity induced by low doses of apomorphine was also unchanged, as was L-DOPA-induced locomotor hyperactivity in mice. Apomorphine-induced climbing in mice was attenuated by (+)-OXA. Clonidine locomotor hypoactivity and hypothermia were unchanged, and clonidine-induced aggressiveness was attenuated by (+)-OXA. Neither OXA enantiomer affected the action of oxotremorine. In some tests the effect of OXA was stronger at 3 h than at 1 h after administration. The above results indicate that both OXA enantiomers--in particular (-)-OXA--increase some dopaminergic behavioural effects in rats.
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PMID:Some central pharmacological effects of (+)- and (-)-oxaprotiline. 231 15

Are ascending noradrenergic and serotonergic pathways necessary for effects of electroconvulsive treatment? Clonidine hypothermia and forced swim study. W. DANYSZ , W. KOSTOWSKI, M. HAUPTMANN, A. BIDZINSKI. Pol. J. Pharmacol. Pharm., 1989, 41, 15-22. Influence of chemical lesions to the noradrenergic locus coeruleus (intracerebral 6-OHDA injection, systemic administration of DSP-4) and serotonergic raphe system (intracerebral 5,7-DHT) on some effects produced by electroconvulsive shock (ECS) was studied. Administration of ECS slightly but significantly attenuated clonidine (CLO)-induced hypothermia and reduced rats immobility in forced swim test. DSP-4 reduced ECS action on CLO hypothermia remaining without effect upon ECS action in the second test. Other lesions were ineffective in both tests. This finding is in contrast to results obtained previously in animals receiving desipramine. The possible difference between ECS and antidepressant drugs action is discussed.
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PMID:Are ascending noradrenergic and serotonergic pathways necessary for effects of electroconvulsive treatment? Clonidine hypothermia and forced swim study. 251 61

The acute effects of the alpha-2 adrenoceptor agonists, clonidine and guanfacine, upon antinociception, hypothermia and motor activity were compared under conditions of receptor antagonism, denervation, and chronic administration of a tricyclic antidepressant compound. The analgesic actions of clonidine and guanfacine were antagonised by idazoxan, an alpha-2 receptor antagonist, but potentiated by pretreatment with the noradrenaline neurotoxin DSP4, and attenuated by chronic treatment with desipramine (DMI). Clonidine- and guanfacine-induced hypothermia was antagonised by idazoxan, potentiated by prior treatment with DSP4 and attenuated by chronic administration with DMI. Both clonidine and guanfacine produced decreases in motor activity that were attenuated by idazoxan but unaffected by prior DSP-4 treatment. Chronic DMI administration also attenuated clonidine-induced hypoactivity but potentiated guanfacine-induced hypoactivity. These diverse results describe both similar and differential adaptive mechanisms modulating the functional effect of alpha-2 receptor systems in the central nervous system.
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PMID:Adaptive changes in alpha-2 adrenoceptor mediated responses: analgesia, hypothermia and hypoactivity. 257 52

We studied a 66-year-old woman with spontaneous periodic hypothermia (Shapiro's syndrome) to determine the mechanisms that result in increased plasma norepinephrine (NE) levels. In comparison with age-matched control subjects, compartmental analysis of NE kinetics revealed an increased NE release rate into the extravascular compartment and decreases in NE clearance and volume of distribution of NE in the intravascular compartment. Clonidine therapy was associated with an initial dramatic decrease in the frequency of diaphoretic episodes as well as with a fall in NE release rate and increases in NE clearance and volume of distribution. We conclude that increased NE release and decreased plasma NE clearance result in elevated plasma NE levels in Shapiro's syndrome. Clonidine, which was associated with changes in NE kinetics, may provide effective treatment for this disorder.
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PMID:Altered norepinephrine metabolism in Shapiro's syndrome. 291 Feb 61

The effect of tizanidine [5-chloro-4-(2-imidazolin-2-yl-amino)-2,1, 3-benzothiadiazole] on core temperature in the mouse was investigated in comparison with that of clonidine. Tizanidine decreased core temperature in unanaesthetized, freely-moving normal mice. Clonidine produced hypothermia in normal mice. The alpha 2-antagonist yohimbine produced an antagonism to tizanidine- and clonidine-induced hypothermia, while naloxone failed to antagonize the hypothermia. It is concluded that tizanidine and clonidine produce a similar hypothermic effect via an alpha 2-adrenoreceptor, but not an endogenous opioid system.
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PMID:Effect of tizanidine on body temperature in the mouse. 371 1


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