Effect of extrinsic denervation on the rate of net water transport of the feline gall bladder.

The influence on the concentrating ability of the gall bladder after extrinsic denervation was studied in anaesthetised cats, previously subjected to truncal vagotomy and/or coeliacectomy , and compared with sham operated controls. Net water absorption was studied by perfusion techniques. Acute experiments were performed under basal conditions and alpha-adrenoceptor stimulation (intra-arterial infusion of noradrenaline). Gall bladder biopsies were studied by fluorescence microscopy and cytofluorimetry to visualise and quantify catecholamines. Three weeks after coeliacectomy basal absorption had decreased significantly. In the short term vagotomy group no changes were shown. In the long term vagotomy group, however, there was a four-fold increase in absorptive capacity, which decreased to control levels after alpha-adrenoceptor blockade (phentolamine). Long term vagotomy with subsequent coeliacectomy caused no significant changes. Infusion of noradrenaline increased net water absorption by 60 +/- 11% in all experimental groups except in long term vagotomised animals, where the high basal absorption was not further augmented. One hour after noradrenaline infusion controls returned to basal absorption rate, while denervated cats remained at stimulated levels. In long term vagotomised gall bladders there were morphological signs of adrenergic proliferation (increased total number of nerve terminals, sprouting and raised levels of intraneuronal noradrenaline). These results suggest that the adrenergic nervous system is important for full absorptive capacity of the gall bladder. The increased absorption after long term vagotomy, abolished after alpha-adrenoceptor blockade, might well be explained by the parallel adrenergic proliferation. This hypothesis was further corroborated in animals with long term vagotomy, where subsequent surgical adrenergic denervation restored basal absorption to control levels.