Effects of alpha-MSH on kainic acid induced changes in core temperature in rats.
The effects of intraperitoneal (i.p.) administration of kainic acid (KA) and alpha-melanocyte-stimulating hormone (alpha-MSH) alone or in combination, on core temperature of freely moving rats were examined. KA or saline was administered once (10 mg/kg) and alpha-MSH or saline was given repeatedly i.e. 10 min before and 10, 30 and 60 min after the administration of saline or KA. Two doses of alpha-MSH were used: 0.5 and 2.5 mg/kg. KA alone produced a biphasic effect on core temperature, i.e. an initial short-lasting hypothermia followed by hyperthermia that lasted about 6 h. The higher dose of alpha-MSH had a potentiating effect on KA-induced hypothermia, while the lower dose of alpha-MSH increased the hyperthermia produced by KA. alpha-MSH administered alone produced a late (3 h), dose-dependent increase in core temperature. It is conceivable that repeated administration of alpha-MSH in the doses used in our study may cause a cumulative effect in raising body temperature for a limited period of time. The previously described interactions between KA and alpha-MSH, respectively, with dopaminergic and serotoninergic systems may account for the effects on core temperature in rats observed in our study.
Oprica
M
M
Division of Geriatric Medicine, Department of NEUROTEC, Karolinska Institute, Huddinge Hospital, Novum, SE-141 86, Huddinge, Sweden. Mircea.Oprica@neurotec.ki.se
Forslin Aronsson
A
A
Post
C
C
Eriksson
C
C
Ahlenius
S
S
Popescu
L M
LM
Schultzberg
M
M
D000818:Animals; D001831:Body Temperature / Q000187:drug effects*; D004305:Dose-Response Relationship, Drug; D007035:Hypothermia; D007608:Kainic Acid / Q000378:metabolism*; D008297:Male; D051381:Rats; D017207:Rats, Sprague-Dawley; D013997:Time Factors; D000521:alpha-MSH / Q000494:pharmacology*
D000521:alpha-MSH; D007608:Kainic Acid