Opioids acting on delta-receptors modulate Ca2+ currents in cultured postganglionic neurones of avian ciliary ganglia.
Opioid agonists inhibited Ba2+ currents in cultured postganglionic neurons of 3-15-day-old embryonic avian ciliary ganglia. Leucine-enkephalin (LENK, 10-20 microM) inhibited transient Ba2+ currents by 50% and sustained currents by 21%. The delta-opioid receptor agonist, DPDPE (0.02-10 microM), also inhibited Ba2+ currents, but kappa- (U50488H) and mu- (DAMGO) receptor agonists had no effect. Inhibition of Ba2+ currents showed profound desensitisation during prolonged application of agonists, being reduced to approximately 25% of the original response after 4 min superfusion with leucine-enkephalin (10-20 microM).
Motin
L G
LG
Physiology Department, University of Sydney, NSW, Australia.
Bennett
M R
MR
Christie
M J
MJ
D000700:Analgesics / Q000494:pharmacology; D000818:Animals; D001464:Barium / Q000494:pharmacology; D015220:Calcium Channels / Q000187:drug effects*; D002478:Cells, Cultured / Q000187:drug effects; D020875:Enkephalin, Ala(2)-MePhe(4)-Gly(5)-; D004745:Enkephalins / Q000494:pharmacology; D005724:Ganglia / Q000187:drug effects*; D008564:Membrane Potentials / Q000187:drug effects; D009294:Narcotics / Q000494:pharmacology*; D017465:Receptors, Opioid, delta / Q000187:drug effects*; D013997:Time Factors
D000700:Analgesics; D015220:Calcium Channels; D004745:Enkephalins; D009294:Narcotics; D017465:Receptors, Opioid, delta; D020875:Enkephalin, Ala(2)-MePhe(4)-Gly(5)-; D001464:Barium