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).

RESULTS Infusion of several neuropeptides stimulated IgA output. Somatostatin (10⁻⁸M) 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.