Nitric oxide in the control of submandibular gland function in the anaesthetized ferret

Abstract

SUMMARYStimulation of the parasympathetic innervation of the submandibular gland (2 or 20 Hz continuously or 20 Hz for 1 s at 10 s intervals), in the ferret, produced secretion of fluid and protein and a fall in vascular resistance. The responses following the administration of NW-nitro-L-arginine methyl ester (L-NAME; 2 mmol kg-' I.A.) to block the synthesis of nitric oxide (NO) were reduced, and the persisting responses were abolished (at 2 Hz continuously and 20 Hz intermittently) or further reduced (at 20 Hz continuously) by the additional administration of atropine. The output of vasoactive intestinal peptide (VIP) from the gland was not affected. Neither the secretory nor the vascular response to intra-arterial infusions of acetylcholine (1 25 nmol kg-1) was affected by L-NAME, whereas the vascular responses to both VIP (10 pmol kg-1) and pituitary adenylate cyclase-activating peptide(1_38) (PACAP) (0(5 pmol kg-') were reduced thereby. Neither peptide evoked a fluid secretion per se. However, when infused during parasympathetic stimulation of saliva secretion, VIP increased both flow rate and the output of protein. These effects of VIP were abolished by L-NAME. The experiments were performed in the presence of sodium nitroprusside at doses (4-8 nmol min-' kg-' i.v.) aimed to counterbalance the systemic effects of L-NAME. The results show that, in the ferret, parasympathetic nerve activity increases submandibular blood flow, and elicits the flow of saliva and output of protein by mechanisms that involve in situ generation of NO, upon which the effects of VIP and PACAP but not acetylcholine are largely dependent.

The role of nitric oxide in the control of protein secretion in the parotid gland of anaesthetized sheep

“…The results of this study confirm the fact that there is a remarkable synergy between the parasympathetic and sympathetic innervations of the parotid gland in the sheep with regard to the secretion of protein from the gland (Edwards & Titchen, 1992 (Buckle et al 1995;Tobin et al 1997), the increase in the flow of saliva and Na+ output in response to stimulation of the parasympathetic innervation were both significantly reduced after L-NAME. However, the concentrations of both Na+ and K+ appeared to be related to the flow of saliva in the same way before and after the administration of L-NAME.…”

“…Nitric oxide (NO) has been implicated in the production of salivary protein in the cat and ferret (Buckle, Parker, Bloom & Edwards, 1995;Edwards, Tobin, Ekstrom & Bloom, 1996;Tobin, Edwards, Bloom & Ekstrom, 1997). In these and other species much evidence has accumulated to associate the neuropeptide vasoactive intestinal peptide (VIP) in the control of salivary protein secretion as well.…”

Immunohistochemical Study of the Innervation of the Boundary Area of the Hard and Soft Palates of the Rat

“…Coexistence of VIP with c-PON within nerve fibers in the cavernous and spongious bodies, the glans penis and the urethra has been shown [Hauser-Kronberger et al, 1994]. Neuromessengers have been shown to stimulate secretion from exocrine glands and vasodilatation [Lundberg et al, 1980;Brain et al, 1985;Gazelius et al, 1987;Tobin et al, 1997;Mirfendereski et al, 1997]. These suggest regulation of blood flow and secretion of exocrine glands in the boundary area of the palate in conjunction with the sensory information.…”

High-resolution electrophoretic analysis of rat parotid salivary proteins

“…The silver-stained 2-DE patterns of rat parotid saliva indicate that (i) the protein composition of the atropine-associated NANC secretion is similar to that evoked in response to parasympathetic nerve stimulation in the absence of muscarinic receptor blockade, (ii) if nitric oxide does play a role in parasympathetic stimulation in the rat (analogous to that observed in the ferret [41]) then it does…”