Catechol blocks the fast outward potassium current in melanotrophs of the rat pituitary.
The effect of catechol on the fast voltage-gated K+ current (IK(f)) of acutely dissociated rat melanotrophs was investigated in whole-cell recordings. Half-maximal inhibition of IK(f) occurred at an external concentration of 1.7 mM and this effect was associated with a decrease of the rate of the current decay. Internal catechol had no measurable effect on IK(f). Catechol appeared to be equally effective as a blocker of the slow voltage-gated K+ current (IK(s)). Despite this lack of specificity the blocking action of catechol was voltage- and frequency-independent and was rapidly reversible. Catechol therefore represents a useful alternative to 4-aminopyridine as a blocker of IK(f).
Kehl
S J
SJ
Department of Physiology, University of British Columbia, Vancouver, Canada.
D000818:Animals; D002396:Catechols / Q000494:pharmacology*; D005071:Evoked Potentials / Q000187:drug effects; D066298:In Vitro Techniques; D007700:Kinetics; D008297:Male; D009074:Melanocyte-Stimulating Hormones / Q000378:metabolism*; D010902:Pituitary Gland / Q000378:metabolism / Q000502:physiology*; D015221:Potassium Channels / Q000187:drug effects / Q000502:physiology*; D051381:Rats; D011919:Rats, Inbred Strains; D013779:Tetrodotoxin / Q000494:pharmacology
D002396:Catechols; D015221:Potassium Channels; D013779:Tetrodotoxin; D009074:Melanocyte-Stimulating Hormones; C034221:catechol