Temperature Regulation and the Hypothalamus

Ke, Cooper

doi:10.1093/oxfordjournals.bmb.a070480

Cited by 35 publications

(11 citation statements)

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“…It has been suggested that they might alter cerebral blood flow (Cooper, 1966) to create a local change in brain temperature. However, Andersson et al (1966) noted a decrease in hypothalamic temperature in the goat while heat loss mechanisms were responding to 5-HT.…”

Section: Discussionmentioning

confidence: 99%

The effect of intraventricular injections of noradrenaline, 5‐hydroxytryptamine, acetylcholine and tranylcypromine on the ox (Bos taurus) at different environmental temperatures

Findlay¹,

Thompson²

1968

The Journal of Physiology

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SUMMARY1. Noradrenaline, 5-hydroxytryptamine (5-HT), acetylcholine and tranylcypromine were injected or infused into the lateral ventricle of the ox. The effects of these drugs on heart and respiration rates, heat production, rectal, skin and hypothalamic temperatures and skin evaporative loss were measured when the animal was exposed to environmental temperatures ranging from -1°C to + 300 C.2. Acetylcholine (0x001-2 mg) had no detectable effect on temperature regulation at 200 C.3. In small doses (0*005-0-05 mg) 5-HT had no detectable effect. Larger doses (2-5 mg) given in a cold environment (-1°C) also had no effect but the same doses given in warm environments (15300 C) caused increases in skin temperatures, skin evaporative loss and respiratory rate, and decreases in rectal and hypothalamic temperatures. 4. Infusion of tranylcypromine (0.107 ml./min of a 1 in 50 solution) in a warm environment (200 C) also caused a decrease in rectal temperature after a delay of 1-1 hr during which no effects were apparent.5. Noradrenaline (2 mg) had no effect on temperature regulation when injected into animals in a warm environment (300 C). When injected (1 mg) into animals in a cold environment (-1°C) shivering stopped and heat production and rectal and hypothalamic temperatures were decreased.6. It is concluded that intraventricular 5-HT and noradrenaline both cause a decrease in body temperature, and it is unlikely that central temperature regulation in the ox is mediated only by these two substances.

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Section: Discussionmentioning

confidence: 99%

The effect of intraventricular injections of noradrenaline, 5‐hydroxytryptamine, acetylcholine and tranylcypromine on the ox (Bos taurus) at different environmental temperatures

Findlay¹,

Thompson²

1968

The Journal of Physiology

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“…Cooper (1966) has reviewed evidence concerning the role of hypothalamic amines in the control of body temperature. The evidence for the importance of either NA or 5-HT is based on the alteration of body temperature by intraventricular injections, a route which is assumed to bypass the blood-brain barrier.…”

Section: Discussionmentioning

confidence: 99%

THE INTERRELATION OF HYPOTHERMIA AND DEPLETION OF NORADRENALINE, DOPAMINE AND 5‐HYDROXYTRYPTAMINE FROM BRAIN BY RESERPINE, p‐CHLOROPHENYLALANINE AND α‐METHYLMETATYROSINE

Somerville¹,

Whittle²

1967

British Journal of Pharmacology and Chemotherapy

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It was shown in 1955 by Pletscher, Shore & Brodie that the sedative and autonomic effects of reserpine in animals were associated with the depletion of 5-hydroxytryptamine (5-HT) and catecholamines from central and peripheral stores. Because of its lack of specificity reserpine is an unsatisfactory tool for distinguishing between the effects of depletion of noradrenaline (NA) and dopamine (DA) on the one hand and 5-HT on the other. Agents are now available which will deplete either catecholamines or 5-HT specifically and we have compared the effects of these depleting agents on body temperature with that of reserpine.The drugs which we have used for this purpose are p-chlorophenylalanine, an inhibitor of tryptophan hydroxylase, which has been shown by Koe & Weissman (1966) to deplete the brain 5-HT of rats to less than 10% of normal without appreciably affecting the catecholamine concentrations, and a-methyl-m-tyrosine (a-MMT), which depletes NA and DA without lowering 5-HT. The time course of the action of a-MMT is such that at 4 hr depletion of both NA and DA is maximal, while at 17 hr NA is still lowered and recovery of DA is almost complete (Moore, 1966).A preliminary account of this work was given at the British Pharmacological Society meeting in Nottingham on January 6, 1967. METHODS p-Chlorophenylalanine (p-C1-Phe) was kindly supplied by Pfizer Ltd. Other drugs were obtained commercially. p-Cl-Phe and a-MMT were injected as ball-milled suspensions or as solutions prepared by dissolving the amino acid in N/I sodium hydroxide and adding N/10 HCI to give a solution of pH 6-7. p-CI-Phe was given at the rate of 150 mg/kg intraperitoneally twice daily for 3 days. This regime was adopted since the single dose of 316 mg/kg used by Koe & Weissman (1966) was found to be much less active in mice than in rats. a-MMT was given at the rate of 100 mg/kg intraperitoneally 4 or 17 hr before reserpine. The hydrochloride of phenoxybenzamine, propranolol (Inderal), guanethidine sulphate and bretylium tosylate were dosed at the rate of 30 mg base/kg subcutaneously.

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“…Ever since the monoamines present in the hypothalamus of the cat were implicated in the control of body temperature (Feldberg & Myers, 1964), the important question concerning their role in the thermoregulation of man and other primates has persisted (Cooper, 1966). In several vertebrate species, 5-HT or a catecholamine, such as noradrenaline, injected intracerebrally produce hyper-or hypothermia depending upon the species used and the doses of the amine given (Cooper, Cranston & Honour, 1965;Allen & Marley, 1966;Bligh, 1966;Feldberg, Hellon & Myers, 1966;Findlay & Robertshaw, 1967;Myers & Yaksh, 1968).…”

Section: Introductionmentioning

confidence: 99%

Control of body temperature in the unanaesthetized monkey by cholinergic and aminergic systems in the hypothalamus

Myers¹,

Yaksh²

1969

The Journal of Physiology

174

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SUMMARY1. In the unanaesthetized rhesus monkey, 5-hydroxytryptamine (5-HT), catecholamines, acetylcholine or carbachol were micro-injected in a volume of 1 0 #l. or less through chronically implanted cannulae at eighty-six sites in the hypothalamus.2. 5-HT in doses of 2-10 ,tg caused a long-lasting elevation in temperature which was dose-dependent. An anatomical 'mapping' of the hypothalamus revealed that the hyperthermic action of 5-HT was localized to the anterior, pre-optic area directly ventral to the anterior commissure.3. Noradrenaline in doses of 1-12 jtg produced a dose-dependent fall in temperature of short duration. An anatomical 'mapping' showed that the hypothermic action of this and other catecholamines was again localized to the anterior, pre-optic region.4. Acetylcholine, alone or in a mixture with eserine, or carbachol caused a dose-dependent hyperthermia which was characterized by an intense rise of short duration and vigorous shivering. A 'mapping' of this response revealed a diffuse patterning of sites throughout the hypothalamus which were sensitive to the application of acetylcholine and carbachol. However, in one circumscribed region at the junction between the posterior hypothalamus and mesencephalon, the two cholinomimetic substances caused a marked fall in temperature.5. We conclude that 5-HT activates a cholinergic heat production pathway which projects from the anterior to posterior hypothalamus. Noradrenaline, on the other hand, blocks the hyperthermic action of 5-HT rather than activates the heat loss system. A chemically mediated heat loss pathway apparently does not exist in the hypothalamus.

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Temperature Regulation and the Hypothalamus

Cited by 35 publications

References 0 publications

The effect of intraventricular injections of noradrenaline, 5‐hydroxytryptamine, acetylcholine and tranylcypromine on the ox (Bos taurus) at different environmental temperatures

The effect of intraventricular injections of noradrenaline, 5‐hydroxytryptamine, acetylcholine and tranylcypromine on the ox (Bos taurus) at different environmental temperatures

THE INTERRELATION OF HYPOTHERMIA AND DEPLETION OF NORADRENALINE, DOPAMINE AND 5‐HYDROXYTRYPTAMINE FROM BRAIN BY RESERPINE, p‐CHLOROPHENYLALANINE AND α‐METHYLMETATYROSINE

Control of body temperature in the unanaesthetized monkey by cholinergic and aminergic systems in the hypothalamus

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