VASCULAR PROTEIN LEAKAGE IN THE RAT PAROTID-GLAND ELICITED BY REFLEX STIMULATION, PARASYMPATHETIC NERVE-STIMULATION AND ADMINISTRATION OF NEUROPEPTIDES

Evans blue accumulated in parotid glands of conscious rats in response to feeding (over 60 min), in the absence of atropine and adrenoceptor antagonists and in their presence, and after pretreatment with the se nsory neurotoxin capsaicin. Stimulation of the auriculo-temporal nerve (40 Hz, 10 or 20 min), without and with the blockers, caused Evans bl ue to accumulate. A periglandular oedema also contained the dye. Admin istration (i.v.) of neurokinin A accumulated Evans blue, while substan ce P, vasoactive intestinal peptide (VIP), pituitary adenylate cyclase -activating peptide (PACAP), calcitonin gene-related peptide (CGRP) an d pilocarpine lacked effect. Pilocarpine enhanced the action of neurok inin A and, furthermore, substance P combined with either VIP, PACAP o r CGRP resulted in accumulation of Evans blue. In the sublingual + sub mandibular glands, Evans blue increased in response to neurokinin A an d pilocarpine; furthermore, substance P and VIP, and substance P and C GRP, interacted positively. Bradykinin lacked effect in the glands. Co mparisons were made with the urinary bladder. Accumulation of Evans bl ue reflects plasma protein extravasation. In salivary glands, the phen omenon occurred during feeding and was independent on intact sensory i nnervation; instead, the parasympathetic innervation containing the ne uropeptides was in focus. In the clinic, the present findings may have implications for the aetiology of gland swelling and pain. (C) 1998 E lsevier Science B.V. All rights reserved.