Ion and ion channel involvement in alpha-melanocyte-stimulating hormone secretion from superfused slices of rat hypothalamus.
Release of alpha-melanocyte-stimulating hormone (alpha-MSH) from 250 micron frontal slices of rat hypothalamus superfused at 37 degrees C with oxygenated artificial cerebrospinal fluid (ACSF) was quantified in freeze-dried samples of ACSF by radioimmunoassay. Significant reproducible increases in alpha-MSH release were caused by 40-70 mM K+ in ACSF, maximum release being caused by 50 mM K+. Fifty mM K+-stimulated alpha-MSH release was abolished in the absence of Ca2+ from ACSF and by the presence of 10(-6) M tetrodotoxin. Tetrapentylammonium ions, 10(-4) M and 10(-3) M, stimulated dose-dependent increases in alpha-MSH release. The data support a putative neurotransmitter/neuromodulator role for alpha-MSH in the CNS.
Tiligada
E
E
Department of Pharmacology and Therapeutics, University of Wales College of Medicine, Heath Park, Cardiff, U.K.
Wilson
J F
JF
D000818:Animals; D002118:Calcium / Q000502:physiology; D007031:Hypothalamus / Q000187:drug effects / Q000378:metabolism*; D066298:In Vitro Techniques; D008297:Male; D015221:Potassium Channels / Q000187:drug effects / Q000502:physiology*; D051381:Rats; D011919:Rats, Inbred Strains; D013779:Tetrodotoxin / Q000494:pharmacology; D000521:alpha-MSH / Q000378:metabolism*
D015221:Potassium Channels; D013779:Tetrodotoxin; D000521:alpha-MSH; D002118:Calcium