The effect of altered 5-hydroxytryptamine levels on beta-endorphin content in rat brain.
The purpose of the present study was to examine the effect of altering the concentration of 5-hydroxytryptamine (5-HT) on beta-endorphin (beta-Ep) content in the hypothalamus, thalamus, and periaqueductal gray (PAG)-rostral pons regions of the rat brain. The selective 5-HT reuptake inhibitor, fluoxetine (10 mg/kg), significantly lowered beta-Ep content in the hypothalamus and the PAG. Parachlorophenylalanine, which inhibits 5-HT synthesis, significantly elevated beta-Ep in all brain parts studied. Intracisternal injections of the neurotoxin, 5',7'-dihydroxytryptamine, with desmethylimipramine pretreatment, significantly increased beta-Ep content in the hypothalamus and the PAG. In adrenalectomized rats, fluoxetine significantly decreased beta-Ep levels in the hypothalamus and increased the levels in the PAG. The results indicate that 5-HT may modulate the levels of brain beta-Ep.
D015116:5,7-Dihydroxytryptamine / Q000494:pharmacology; D000315:Adrenalectomy; D000818:Animals; D001921:Brain / Q000378:metabolism*; D002997:Clomipramine / Q000494:pharmacology; D004723:Endorphins / Q000378:metabolism*; D010134:Fenclonine / Q000494:pharmacology; D005473:Fluoxetine / Q000494:pharmacology; D007031:Hypothalamus / Q000378:metabolism; D010487:Periaqueductal Gray / Q000378:metabolism; D051381:Rats; D012701:Serotonin / Q000502:physiology*; D009435:Synaptic Transmission / Q000187:drug effects; D013788:Thalamus / Q000378:metabolism; D001615:beta-Endorphin
D004723:Endorphins; D005473:Fluoxetine; D015116:5,7-Dihydroxytryptamine; D012701:Serotonin; D001615:beta-Endorphin; D002997:Clomipramine; D010134:Fenclonine