Lack of effect of 4-aminopyridine on acute resetting of the type I carotid baroreceptor.
Acute resetting of the type I carotid baroreceptor was examined before and after exposure to 10(-4) M 4-aminopyridine (4-AP), a blocker of the transient K+ A current (IA), using a vascularly isolated carotid sinus preparation in thiopental anesthetized dogs. Type I baroreceptor firing patterns were analysed to determine threshold pressure (Pth) at different conditioning pressures. Additionally, the ability of 10(-4) M 4-AP to induce vasoconstriction in canine carotid sinus, internal carotid and common carotid artery vascular ring segments was tested as a possible contributing mechanism to resetting. Our findings demonstrated that 10(-4) M 4-AP did not alter acute baroreceptor resetting or induce carotid artery vasoconstriction.
Drummond
H A
HA
Zablocki Department of Veterans Affairs Medical Center, Milwaukee, WI.
Seagard
J L
JL
D015761:4-Aminopyridine / Q000494:pharmacology*; D000200:Action Potentials / Q000187:drug effects; D000818:Animals; D002339:Carotid Arteries / Q000187:drug effects*; D004285:Dogs; D066298:In Vitro Techniques; D009131:Muscle, Smooth, Vascular / Q000187:drug effects; D009475:Neurons, Afferent / Q000187:drug effects; D015221:Potassium Channels / Q000187:drug effects / Q000378:metabolism; D011311:Pressoreceptors / Q000187:drug effects*; D014661:Vasoconstriction / Q000187:drug effects
D015221:Potassium Channels; D015761:4-Aminopyridine