Alamethicin-evoked catecholamine release from cat adrenal glands |
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Authors: | A R Artalejo C Montiel P Sánchez-García G Uceda J M Guantes A G García |
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Affiliation: | Departamento de Ciencias Médicas Básicas, Facultad de Medicina de Lérida, Universidad de Barcelona, Spain. |
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Abstract: | Alamethicin enhances the rate of catecholamine output from perfused cat adrenal glands in a concentration-dependent manner. At 37 degrees C, catecholamine released went from 4.29 +/- 0.25 to 20.51 +/- 0.63 micrograms/stimulus at ionophore concentrations ranging from 20 to 100 micrograms/ml. Secretion was abolished at 22 degrees C or in the absence of extracellular Ca. The time-course of secretion (quick activation followed by a decline) evoked by alamethicin considerably differs from the catecholamine release pattern seen with A23187, X537A or ionomycin, which evoke a slowly developing, non-inactivating secretory response. In fact, its transient secretion pattern resembles that of nicotinic or high-K stimulation of cat adrenal glands, thus suggesting that alamethicin might form Ca permeable artificial channels in chromaffin cell plasma membranes. |
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