Alterations of offspring heart muscle electrical activity transferred by rat male genitors chronically treated with lindane (7-hexachlorocyclohexane) trace concentrations

Abstract : Using intracellular microelectrodes, we Studied transmembrane resting and action potentials (AP) of left ventricle papillary muscles isolated from the heart of adult lindane-treated (TMG) and untreated (UMG) male genitor rat offspring, obtained by mating untreated female with males chronically treated and untreated with lindane (2 ppb) trace concentrations through beverage. The AP magnitude and duration (APD) were similar in both groups and their response to low temperature (22 degrees C) unchanged. Lowering the external Ca2+ concentration from 2.5 to 0.625 mM prolonged APD in the TMG group but not in the UMG group. In the TMG group, (i) cumulative addition of Sr2+ (1 mM) to the physiological Solution prolonged APD; (ii) apamin (4 mu M) and charybdotoxin (4 mu M) prolonged the APD. In conclusion, our data revealed that an altered sensitivity of the Ca2+-induced Ca2+ inactivation of L-type Ca2+ channels and of Ca2+-activated K+ channels to Ca2+ has been transferred to TMG offspring. (cop) 2006 Elsevier Inc. All rights reserved.