The effects of MIF-I, beta-endorphin and alpha-MSH on d-amphetamine induced paradoxical behavioral thermoregulation: possible involvement of the dopaminergic system.
The neuropharmacological basis for d-amphetamine induced paradoxical behavioral thermoregulation remains unclear. This study examined thermoregulatory behavior of rats in a runway device that housed a heat source at one end and in which locomotion along the length of the runway could be observed. Sprague Dawley rats were pretreated with IP injections of saline, beta-endorphin, MIF-1, or alpha-MSH, with a repeat injection after 30 min. In a second experiment, d-amphetamine was administered as the repeat drug for all Ss. The results showed clear differences for heat-source-on vs. heat-source off. All peptides induced hypermotility, although no differentiated effects for the peptides on d-amphetamine induced paradoxical behavioral thermoregulation were found. These findings are discussed in light of the theoretical possibilities that: (a) a ceiling effect exists; (b) there are separate control systems for maintaining body temperature and another for behavioral thermoregulatory responses, and (c) other neurotransmitters may be involved in such induced paradoxical behavioral thermoregulation.
Yehuda
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S
Sheleff
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P
D000818:Animals; D001833:Body Temperature Regulation / Q000187:drug effects*; D003913:Dextroamphetamine / Q000494:pharmacology*; D004298:Dopamine / Q000502:physiology*; D004723:Endorphins / Q000494:pharmacology*; D006358:Hot Temperature; D009075:MSH Release-Inhibiting Hormone / Q000494:pharmacology*; D008297:Male; D009074:Melanocyte-Stimulating Hormones / Q000494:pharmacology*; D009043:Motor Activity / Q000187:drug effects*; D051381:Rats; D011919:Rats, Inbred Strains; D001615:beta-Endorphin
D004723:Endorphins; D001615:beta-Endorphin; D009074:Melanocyte-Stimulating Hormones; D009075:MSH Release-Inhibiting Hormone; D003913:Dextroamphetamine; D004298:Dopamine