Nicotinic receptor/ionic channel complex ( @entity9176 ) in XXXX -dependent skeletal muscle cultures.

@entity35 @entity70754 @entity342 @entity9176
The kinetic properties of the nicotinic receptor/ionic channel complex ( @entity9176 ) were compared in cell cultures obtained from @entity342 -dependent skeletal muscles of the perineal complex (P) and from muscles less dependent upon sex hormones (the thigh musculature, T). Because the development of P is delayed compared to other skeletal muscles in the @entity35 , cultures were performed taking into account the age of the donor (4- or 6-day-old @entity35 ), and the time interval the cells remained in culture (7 days and 15 days). The ionic channel conductance (gamma) and the mean channel open time (tau) were determined with the patch-clamp technique in the cell-attached configuration at room temperature. Cultures from P and T muscles were morphologically identical in size and shape, independent of the animals' age at plating or on the plating time. In all of them, the @entity9176 was spread over the cell membrane. More than one @entity9176 ionic channel conductance was observed in P and T cultures, and the prevalent value of gamma in either culture ranged from 30 pS to 35 pS. In P fibers from 4-day-old @entity35 cultured for 7 days (P 4/7), the distribution of channel open times fitted a double exponential, while in T 4/7 they were fitted with a single exponential. In cultures from P and T muscles obtained from older @entity35 (6 days old) and in those cells remaining in culture for a prolonged time (15 days), the channel open times also fitted a double exponential. Because P and T cultures lack trophic neuronal influences, the difference observed between the tau of @entity70754 was thought to be the hormone requirement of P muscles to grow and differentiate. Likewise, the difference observed between T 4/7 and T 4/15 may indicate the need for neurotrophic influences to maintain higher tau values in older cultures. Since this requirement is not found in cultured fibers, tau would tend to assume slower values approaching those of P without hormone activation.
