The relationship between alpha 1-adrenergic receptor occupation and the mobilization of intracellular calcium.

摘要: Abstract We have simultaneously quantitated alpha 1-adrenergic receptor occupation and agonist-elicited Ca2+ mobilization monitored as unidirectional 45Ca2+ efflux from intact BC3H-1 muscle cells in order to examine the relationship between number of surface receptors occupied functional response. [3H]Prazosin has been used measure well binding kinetics with receptors, observed equilibrium kinetic constants are close accord values obtained previously cellular homogenates. Since 1-agonist-elicited can be over intervals 3 min or less prazosin dissociation its a t 1/2 44 min, employed produce pseudoirreversible inactivation receptors. A comparison remaining residual response reveals an inverse linear inactivated by efflux. similar result is following fractional irreversible alkylating agent phenoxybenzamine. Parameters also correlate for agonist phenylephrine competitive antagonist phentolamine. The unitary sites available indicates that 1 does not function oligomer where fewer bound molecules required block than necessary activation. Moreover, substantial evidence accrued smooth reserve nonlinear coupling contraction muscle. Our findings demonstrate such behavior exist receptor-elicited cell.