Effect of neuroactive peptides on labeled 5-hydroxytryptamine release from rat spinal slices in vitro.
Effects of neuroactive peptides on the release of labeled 5-hydroxytryptamine (5-HT) from preloaded rat spinal cord slices were investigated. The 5-HT release was significantly stimulated by somatostatin (10-50 microM) and substance P (10-50 microM), but not by neurotensin (50 microM), beta-endorphin (30 microM) and methionine-enkephalin (met-enk) (100 microM). Somatostatin-stimulated 5-HT release was markedly inhibited by gamma-aminobutyric acid (GABA) (30 microM), but not by baclofen (30 microM) and met-enk (100 microM). Substance P-stimulated 5-HT release was strongly inhibited by GABA (30 microM) and baclofen (30 microM), but not by met-enk (100 microM). High concentrations (20 mM) of potassium also stimulated 5-HT release. The high potassium-stimulated 5-HT release was not affected by GABA (30 microM) and met-enk (100 microM). These results suggested further evidence on the important role of somatostatin and substance P as modulators of serotonergic neurones.
D000818:Animals; D001418:Baclofen / Q000494:pharmacology; D004744:Enkephalin, Methionine / Q000494:pharmacology; D066298:In Vitro Techniques; D008297:Male; D009419:Nerve Tissue Proteins / Q000494:pharmacology*; D011188:Potassium / Q000494:pharmacology; D051381:Rats; D011919:Rats, Inbred Strains; D012701:Serotonin / Q000378:metabolism*; D013004:Somatostatin / Q000494:pharmacology; D013116:Spinal Cord / Q000187:drug effects / Q000378:metabolism*; D013373:Substance P / Q000494:pharmacology; D014279:Trigeminal Nucleus, Spinal / Q000187:drug effects / Q000378:metabolism; D005680:gamma-Aminobutyric Acid / Q000502:physiology
D009419:Nerve Tissue Proteins; D012701:Serotonin; D013373:Substance P; D013004:Somatostatin; D005680:gamma-Aminobutyric Acid; D004744:Enkephalin, Methionine; D001418:Baclofen; D011188:Potassium