Ionic requirement for epinephrine stimulation of frog skin gland secretion

Abstract

Abstract The outer surface of isolated frog (R. pipiens) skin was observed through a dissection microscope during addition of epinephrine (2 × 10 −6 w/v) to the inside bathing solution. Small droplets formed at pore openings within 30 seconds; the process appeared to be complete within 1 to 2 minutes. After washing out the bathing solution and a 30 minute recovery period, the response could be repeated up to six times. The gland requires NaCl for multiple responses. Neither added Ca nor added K is required. Cs and K may replace Na but only to a minor extent. Mg, Rb and Li could not substitute for Na. Chloride is the preferred anion, and while NO 3 may be a partially effective substitute, I and SO 4 were not.