[Hydrocortisone inhibits nicotinic acetylcholine receptor response in the rat airway parasympathetic ganglion neurons].
The effect of hydrocortisone on neurons acutely isolated from the rat airway parasympathetic ganglia was investigated by using nystatin perforated-patch recording configuration under the voltage-clamp conditions. Acetylcholine (ACh) evoked inward currents in a concentration-dependent manner with a half maximum effective concentration (EC50) of 3.3 x 10(-5) M at a holding potential of -50 mV. The ACh response was mimicked by nicotine, and it was inhibited by both mecamylamine and hexamethonium. alpha-Bungarotoxin had no effect on the ACh response. Hydrocortisone concentration-dependently inhibited the current induced by 3 x 10(-5) M ACh with a half maximum inhibitory concentration (IC50) of 2.1 x 10(-4) M. The effect of hydrocortisone was voltage-independent. Hydrocortisone suppressed the maximum response of the ACh concentration-response curve, indicating that the inhibitory action of hydrocortisone on the nicotinic ACh response is non-competitive.
Seki
Masamichi
M
Cellular and System Physiology, Graduate School of Medical Sciences, Kyushu University, Fukuoka 812-8582, Japan.
D000109:Acetylcholine / Q000037:antagonists & inhibitors* / Q000494:pharmacology; D000818:Animals; D001980:Bronchi / Q000294:innervation; D002478:Cells, Cultured; D003864:Depression, Chemical; D004305:Dose-Response Relationship, Drug; D005726:Ganglia, Parasympathetic / Q000166:cytology*; D006854:Hydrocortisone / Q000494:pharmacology*; D009474:Neurons / Q000187:drug effects*; D051381:Rats; D011978:Receptors, Nicotinic / Q000187:drug effects*; D014132:Trachea / Q000294:innervation
D011978:Receptors, Nicotinic; D000109:Acetylcholine; D006854:Hydrocortisone