Responses of the denervated rat urinary bladder to alfa adrenoceptor stimulation

The contractile responses of the rat detrusor muscle to noradrenaline were increased 2-3 weeks after partial denervation but had returned to control values 6-9 weeks after the denervation, probably because of reinnervation of denervated muscle cells. 6-9 weeks after partial denervation the excitatory alpha-adrenoceptor mediated response to stimulation of the remaining intact nerves was predominant, masking the subsequent inhibitory beta-receptor response, which at this time was seen only after alpha-receptor blockade. The possibility of an outgrowth of adrenergic fibres activating alpha-receptors in muscle cells normally not innervated by adrenergic nerves is discussed.