Effects of vitamin E deficiency on autonomic neuroeffector mechanisms in the rat caecum, vas deferens and urinary bladder.

Abstract

1. Modified sucrose-gap, standard organ-bath techniques and transmitter release studies were used to examine neuromuscular transmission in the caecum, vas deferens and urinary bladder in normal rats and in rats maintained for 12 months on a diet free of vitamin E. 2. In the caecum circular muscle, non-adrenergic, non-cholinergic inhibitory junction potentials were absent from 48 and 15% of preparations from vitamin E-deficient and control animals, respectively. Cholinergic excitatory junction potentials were absent from 83 and 8% of vitamin E-deficient and control preparations, respectively. Responses to applied noradrenaline (0.1-30 microM), alpha,beta-methylene ATP (3-100 microM) and acetylcholine (0.1-30 microM) were attenuated or absent in vitamin E-deficient tissues. Responses to applied KCl were similar in both groups. Release of [3H]noradrenaline or endogenous acetylcholine could not be evoked from vitamin E-deficient tissues. 3. In contrast, in isolated preparations of the vas deferens and urinary bladder, neuromuscular transmission by adrenergic, cholinergic and purinergic components were unaffected by long-term vitamin E deficiency. 4. In conclusion, vitamin E deficiency causes dysfunction of autonomic neuroeffector mechanisms in the smooth muscle of the rat caecum, at both a pre- and postjunctional level. The lesions in autonomic transmission mechanisms brought about by long-term vitamin E deficiency were found only in the caecum; no changes in sympathetic neuromuscular transmission were observed in the vas deferens, or in parasympathetic neuromuscular transmission in the urinary bladder.