Brain Amines and Temperature Regulation

Summary1. Administration of two doses of amphetamine HCl (5 mg/kg intraperitoneally) 45 min apart raised body temperature of rats by an average of 3.40 C and increased the turnover rate of brain 5-hydroxytryptamine (5-HT) by almost one-half. 2. Both effects were blocked by exposure to 40 C or by pretreatment with the B-blocker Ko 592 (1-(2-methylphenoxy)-3-isopropylamino-2-propanol), but not by the administration of the ganglionic blocker chlorisondamine combined with atropine. 3. Since it has previously been shown that hyperthermia per se increases the turnover rate of brain 5-HT, and that amphetamine does not directly affect the uptake and release of 5-HT in brain slices, it is concluded that the amphetamineinduced increase in 5-HT turnover may be secondary to the rise in temperature produced by the drug.

Section: Discussionmentioning

confidence: 98%

Section: Introductionmentioning

confidence: 99%

Turnover rate of brain 5‐hydroxytryptamine increased by D‐amphetamine

Reid

Derr

1970

“…An increase in brain 5-HT content after A9-THC was also reported by Sofla et al (1971) but not by Gallager et al (1972). Since changes in ambient temperature can alter monoamine metabolism (Reid et al, 1968;Simmonds, 1969;1970), it appears reasonable to suggest that A9-THC has altered the 5-HT metabolism at all four ambient temperatures used.…”

Section: Discussionmentioning

confidence: 99%

THE EFFECT OF Δ⁹‐TETRA‐HYDROCANNABINOL ON BODY TEMPERATURE AND BRAIN AMINE CONCENTRATIONS IN THE RAT AT DIFFERENT AMBIENT TEMPERATURES

Fennessy

Taylor

1977

I Rats were injected intravenously with 2 mg/kg (-)-trans-A9-tetrahydrocannabinol (A9-THC) at ambient temperatures of 40, 2 10, 310 and 370C. 2 The general behaviour exhibited by rats treated with A9-THC was similar at all four ambient temperatures.3 Body temperatures were recorded continuously before and after drug administration. At 40 and 210C, A9-THC caused hypothermia whereas no change in body temperature occurred at 310 and 370C. 4 The concentrations in the whole brain of noradrenaline (NA), dopamine, 5-hydroxytryptamine (5-HT) and 5-hydroxyindoleacetic acid (5-HIAA) were determined spectrophotofluorimetrically 1 h after drug administration. At 40C A9-THC caused an increase of 5-HT, at 21 OC an increase of 5-HIAA, at 31 OC an increase of 5-HIAA and a decrease of NA, and at 370C an increase of 5-HT and 5-HIAA.5 At all ambient temperatures, A9-THC increased the brain levels of 5-HT and/or 5-HIAA. A correlation between the A9-THC-induced hypothermic response and the possible alteration of brain 5-HT metabolism cannot be excluded.

“…Exposure of rats to heat or cold increases the turnover of noradrenaline (NA) in whole brain (Costa & Neff, 1966;Gordon, Spector, Sjoerdsma & Udenfriend, 1966;Corrodi, Fuxe & Hokfelt, 1967;Duce, Crabai, Vargiu, Piras, Adamo & Gessa, 1968;Reid, Volicer, Smookler, Beaven & Brodie, 1968). These responses occur specifically in the hypothalamus of the rat upon exposure to mild heat or cold (Simmonds, 1969).…”

Section: Introductionmentioning

confidence: 99%

Inhibition by atropine of the increased turnover of noradrenaline in the hypothalamus of rats exposed to cold

Simmonds

1971

Summary1. Small doses of (-)-[3H] noradrenaline were injected into the lateral cerebral ventricles in rats to label radioactively the endogenous noradrenaline (NA) stores.2. Intraventricular injection of 25 1ug atropine methonitrate at the same time inhibited the increased rate of disappearance of [3H] NA from the hypothalamus at an environmental temperature of 90 C, when compared with the values at 240 C, without impairing temperature regulation. 3. At 320 C, 25 jtg atropine methonitrate caused a lethal hyperthermia. A dose of 5 yg was not lethal and did not inhibit the increased rate of disappearance of [3H] NA from the hypothalamus. 4. It is concluded that the pathway which stimulates an increased turnover of NA in the cold contains an atropine sensitive synapse but is not the principal pathway of heat production. The increased turnover of NA in the heat probably does not involve an atropine sensitive synapse.