Release of alpha-melanocyte stimulating hormone into rat and human cerebrospinal fluid in vivo and from rat hypothalamus slices in vitro.
The release of alpha-melanocyte stimulating hormone (alpha-MSH) from central nervous system neurons was investigated and demonstrated in vivo and in vitro. alpha-MSH immunoreactivity in rat and human cerebrospinal fluid (CSF) is comprised of deacetylated alpha-MSH, alpha-MSH and the methionine sulfoxide forms of these peptides. The sulfoxides are formed artifactually upon extraction. alpha-MSH in rat CSF is unaffected by hypophysectomy but is markedly increased by electrical stimulation of the mesencephalic central gray. These data indicate that CSF alpha-MSH is primarily of neuronal origin, alpha-MSH is also released in a calcium dependent manner from hypothalamic slices in vitro. The fact that the release of alpha-MSH is stimulated by veratridine and inhibited by tetrodotoxin demonstrates the necessity for neuronal sodium influx for alpha-MSH release. The presence of an alpha-MSH neurosecretory process supports a neurotropic role for this peptide in the central nervous system.
D000818:Animals; D001921:Brain / Q000502:physiology; D002118:Calcium / Q000494:pharmacology; D004558:Electric Stimulation; D006801:Humans; D007016:Hypophysectomy; D007031:Hypothalamus / Q000187:drug effects / Q000378:metabolism*; D008297:Male; D009074:Melanocyte-Stimulating Hormones / Q000134:cerebrospinal fluid / Q000378:metabolism*; D008636:Mesencephalon / Q000502:physiology; D051381:Rats; D013779:Tetrodotoxin / Q000494:pharmacology; D014701:Veratridine / Q000494:pharmacology
D013779:Tetrodotoxin; D014701:Veratridine; D009074:Melanocyte-Stimulating Hormones; D002118:Calcium