Interacting effects of capsaicin and anandamide on intracellular calcium in sensory neurones.
Capsaicin (100 nM to 1 microM) and anandamide (200 nM to 10 microM) caused a transient increase in fluorescence of fura-2 loaded cultured small trigeminal neurones of rats measured with a ratiometric technique. The percentage of cells responding to capsaicin at 100 nM, 330 nM and 1 microM was 47.4%, 45.3%, and 70.4%, respectively. Averaged peak value of fluorescense ratio (R) at 340 and 380 nm excitation was slightly dose dependent. Peaks of anandamide-induced transients were R = 0.2 at 200 nM and 0.16 at 10 microM. Near 40% of capsaicin-sensitive cells responded also to anandamide. Anandamide (200 nM) inhibited the capsaicin-induced calcium influx. The results suggest that anandamide increases intracellular calcium and inhibits capsaicin-evoked calcium transients.
Szöke
E
E
Neuropharmacology Research Group of Hungarian Academy of Science, Institute of Pharmacology and Pharmacotherapy, University of Pécs.
Balla
Z
Z
Csernoch
L
L
Czéh
G
G
Szolcsányi
J
J
D000818:Animals; D001095:Arachidonic Acids / Q000494:pharmacology*; D002118:Calcium / Q000378:metabolism*; D002121:Calcium Channel Blockers / Q000494:pharmacology*; D002211:Capsaicin / Q000494:pharmacology*; D002478:Cells, Cultured; D004305:Dose-Response Relationship, Drug; D004347:Drug Interactions; D063388:Endocannabinoids; D005456:Fluorescent Dyes; D016257:Fura-2; D007425:Intracellular Membranes / Q000378:metabolism*; D009475:Neurons, Afferent / Q000187:drug effects* / Q000378:metabolism*; D053284:Polyunsaturated Alkamides; D051381:Rats; D017208:Rats, Wistar
D001095:Arachidonic Acids; D002121:Calcium Channel Blockers; D063388:Endocannabinoids; D005456:Fluorescent Dyes; D053284:Polyunsaturated Alkamides; D002211:Capsaicin; D002118:Calcium; D016257:Fura-2; C078814:anandamide