3H-metaraminol releasing action of mescaline from rat hypothalamus in vitro.
The amine releasing action of mescaline was investigated in rat isolated hypothalamus labeled with 3H-metaraminol. Mescaline had no effect on the uptake of 3H-metaraminol but produced its release in a concentration-related manner. 4 x 10(-4) M mescaline, which produced submaximal effects was used for subsequent experiments. 3 x 10(-5) M cocaine had no effect on the 3H-metaraminol releasing action of mescaline. Mescaline was fully effective in Ca2+-free medium while 6 x 10(-2) M KCl was ineffective. 3 x 10(-7) M tetrodotoxin or 6 x 10(-5) M lidocaine partially blocked mescaline-induced release but substantially or completely blocked 3 x 10(-2) M KCl-induced release. Prior exposure of hypothalamus to 3 x 10(-4) M tyramine reduced the releasing action of mescaline. Thus, mescaline appears to release 3H-metaraminol both by Ca2+-independent (tyramine-like) and Ca2+-dependent (lidocaine-sensitive) mechanisms. 3 x 10(-4) M tyramine and 6 x 10(-2) M KCl released 14C from control hypothalamus labelled with 14C-mescaline, but not from reserpinized hypothalamus. The amounts of 14C recovered in 14C-mescaline labeled control and reserpinized hypothalamus at the end of 50 min of efflux were similar suggesting a poor retention of 14C-mescaline by storage particles.
D000818:Animals; D002118:Calcium / Q000502:physiology; D005260:Female; D007031:Hypothalamus / Q000187:drug effects / Q000378:metabolism*; D066298:In Vitro Techniques; D008297:Male; D008635:Mescaline / Q000378:metabolism / Q000494:pharmacology*; D008680:Metaraminol / Q000378:metabolism*; D011189:Potassium Chloride / Q000494:pharmacology; D051381:Rats; D012110:Reserpine / Q000494:pharmacology; D014439:Tyramine / Q000494:pharmacology
D011189:Potassium Chloride; D008680:Metaraminol; D012110:Reserpine; D008635:Mescaline; D002118:Calcium; D014439:Tyramine