Possible mechanism of the stimulatory effect of 4-aminopyridine on toad skin.
1. This study was undertaken to demonstrate the facilitatory effects of 4-aminopyridine on transmitter release in the toad skin preparation. 2. A dose-dependent increase in the bioelectric parameters was found. 3. This effect was blocked by propranolol and by verapamil but not by dibenamine, and was mimicked by the calcium ionophore A-23187 but not by potassium channel blockers. 4. These results support the hypothesis that 4-aminopyridine increases presynaptic nerve terminal permeability of calcium and thus the release of noradrenaline.
González
C S
CS
Department of Physiological Sciences, Faculty of Biological and Natural Sciences, University of Concepcion, Chile.
Norris
B C
BC
Concha
J B
JB
Contreras
G M
GM
D015761:4-Aminopyridine / Q000494:pharmacology*; D000818:Animals; D001001:Anura; D000001:Calcimycin / Q000494:pharmacology; D002121:Calcium Channel Blockers / Q000494:pharmacology; D004594:Electrophysiology; D066298:In Vitro Techniques; D015221:Potassium Channels / Q000187:drug effects; D011941:Receptors, Adrenergic / Q000187:drug effects; D012867:Skin / Q000187:drug effects*; D013268:Stimulation, Chemical
D002121:Calcium Channel Blockers; D015221:Potassium Channels; D011941:Receptors, Adrenergic; D000001:Calcimycin; D015761:4-Aminopyridine