5-Hydroxytryptamine releases adenosine from primary afferent nerve terminals in the spinal cord.
5-Hydroxytryptamine (serotonin, 5-HT) increased the release of endogenous adenosine from dorsal, but not ventral, spinal cord synaptosomes. This release was reduced by (i) the 5-HT receptor antagonist methysergide, (ii) removal of Ca2+ from the medium, (iii) inhibition of ecto-5'-nucleotidase and (iv) capsaicin pretreatment. These data suggest that activation of 5-HT receptors on primary afferent terminals releases a nucleotide which is converted extracellularly to adenosine. This adenosine may contribute to the spinal antinociceptive effect of 5-HT.
Sweeney
M
M
Department of Pharmacology, Dalhousie University, Halifax, N.S., Canada.
White
T
T
Sawynok
J
J
D000241:Adenosine / Q000378:metabolism*; D000818:Animals; D002211:Capsaicin / Q000494:pharmacology; D008297:Male; D008784:Methysergide / Q000494:pharmacology; D009475:Neurons, Afferent / Q000187:drug effects / Q000378:metabolism*; D051381:Rats; D011919:Rats, Inbred Strains; D012701:Serotonin / Q000494:pharmacology*; D013116:Spinal Cord / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D013347:Subcellular Fractions / Q000378:metabolism; D013574:Synaptosomes / Q000187:drug effects / Q000378:metabolism*
D012701:Serotonin; D000241:Adenosine; D002211:Capsaicin; D008784:Methysergide