Prostaglandins block a Ca2+-dependent slow spike afterhyperpolarization independent of effects on Ca2+ influx in visceral afferent neurons.
The blockade of a slow Ca2+-activated K+-dependent afterhyperpolarization (AHPs) in rabbit visceral sensory neurons by the prostaglandins, PGE1 and PGD2, was investigated to determine whether the blockade was indirectly due to a reduction in Ca2+ influx. The prostaglandins (PGs) could block the AHPs in the absence of any change in Ca2+-dependent spikes elicited in the presence of tetrodotoxin and tetraethylammonium bromide. A PG-induced decrease in Ca2+-dependent spike width observed in some neurons was temporally dissociated from the PG-induced block of the AHPs. In addition, a slow afterhyperpolarization produced by the application of the Ca2+ ionophore, A23187, was blocked by the PGs. It is concluded that a reduction in Ca2+ influx is not responsible for the PG-induced blockade of the AHPs.
J C
JC
Fowler
W F
WF
Wonderlin
D
D
Weinreich
D000200:Action Potentials / Q000187:drug effects; D000527:Alprostadil / Q000494:pharmacology; D000818:Animals; D002118:Calcium / Q000037:antagonists & inhibitors* / Q000378:metabolism; D002463:Cell Membrane Permeability / Q000187:drug effects; D066298:In Vitro Techniques; D007473:Ion Channels / Q000187:drug effects; D009620:Nodose Ganglion / Q000187:drug effects*; D011188:Potassium / Q000502:physiology; D015230:Prostaglandin D2; D011453:Prostaglandins / Q000494:pharmacology*; D011457:Prostaglandins D / Q000494:pharmacology; D011817:Rabbits; D014630:Vagus Nerve / Q000187:drug effects*
D007473:Ion Channels; D011453:Prostaglandins; D011457:Prostaglandins D; D000527:Alprostadil; D011188:Potassium; D015230:Prostaglandin D2; D002118:Calcium