Substance P enhances the release of endogenous serotonin from rat ventral spinal cord.
The effect of the tachykinin neuropeptides, substance P (SP), neurokinin A (NKA) and the neurokinin B (NKB) receptor agonist, senktide, on the potassium-evoked release of endogenous serotonin (5-hydroxytryptamine, 5-HT) was investigated in superfused tissue slices of rat ventral spinal cord, where 5-HT is known to coexist with SP. Endogenous 5-HT was assayed by HPLC with electrochemical detection. The evoked release of 5-HT was significantly enhanced by 10(-4) M SP (190% increase) and 10(-5) M SP (74% increase) but not by 10(-6) M SP, NKA (10(-5) and 10(-4) M) and senktide (10(-5) and 10(-4) M) had no significant effect on the 5-HT release. The results suggest that, in the rat ventral spinal cord, where most of the 5-HT and SP is stored in the same nerve endings. SP but not NKA nor NKB potentiates the evoked release of 5-HT in a dose-dependent manner.
Franck
J
J
Department of Physiology, Karolinska Institutet, Stockholm, Sweden.
Fried
G
G
Brodin
E
E
D000818:Animals; D066298:In Vitro Techniques; D008297:Male; D015288:Neurokinin A / Q000494:pharmacology; D010446:Peptide Fragments / Q000494:pharmacology; D011188:Potassium / Q000494:pharmacology; D051381:Rats; D011919:Rats, Inbred Strains; D012701:Serotonin / Q000378:metabolism*; D013116:Spinal Cord / Q000187:drug effects / Q000378:metabolism*; D013373:Substance P / Q000031:analogs & derivatives / Q000494:pharmacology*
D010446:Peptide Fragments; C054724:senktide; D012701:Serotonin; D013373:Substance P; D015288:Neurokinin A; D011188:Potassium