Fast acting nervous regulation of immunoglobulin A secretion from isolated perfused porcine ileum

Abstract

Background - The intestinal mucosa harbours a large number of nerve fibres and also plasma cells, providing the anatomical basis for studies of neuroimmune interactions. Aims - To study the effect of different neurotransmitters and electrical stimulation of the extrinsic intestinal nerves on secretion of immunoglobulin A (IgA). Methods - IgA was measured, using a specific ELISA, in the luminal and venous effluent from isolated vascularly perfused porcine ileal segments with preserved extrinsic nerve supply. Results - Infusion of several neuropeptides stimulated IgA output. Somatostatin (10-8 M) stimulated IgA secretion in the luminal effluent from 46.6 (14.3) to 79.3 (19.0) μg/5 min and increased the venous output to 148.3 (23.0)% (n=6) of basal output, whereas noradrenaline (10-6 M) inhibited the secretion (to 49.2 (6.5)% of basal output, n=6). Electrical stimulation of the mixed extrinsic nerves supplying the intestinal segment had no effect by itself. However, electrical stimulation during infusion of α adrenergic blockers or coinfusion of both α adrenergic and muscarinic blockers resulted in an immediate and significant increase in IgA, an effect that was abolished by nicotinic blockade. Conclusion - The extrinsic nerve supply to the intestine could be involved in fast acting regulation of mucosal immune functions.