Interaction of l - arginine / nitric oxide system with lead acetate on secretion of amylase from isloated rat parotid glands.

ABSTRACT

In the present study the effects of lead acetate and/or L-Arginine as a nitric oxide precursor and L-NAME as a nitric oxide synthase inhibitor on the amylase secretion of rat parotid gland lobules were investigated. Lead acetate in doses of 3, 30 and 300 micro M significantly [P<0.01] caused a dose-dependent reduction in isoproterenol-stimulated or non-stimulated amylase secretion. When secretion of saliva was not stimulated by beta-adrenergic agonist, L-Arginine [100 micro M] significantly [P<0.01] reduced amylase output. L-NAME [100 micro M] alone had no significant effect on amylase output but when used with lead acetate prevented [P<0.01] from lead-induced reduction of amylase output. Both L-NAME [100 micro M] and L-Arginine [100 micro M]] when used alone reduced isoproterenol-stimulated amylase output. Concurrent administration of lead acetate [300 micro M]] with either L-Arginine [100 micro M] or L-NAME [100 micro M] showed a marked positive interaction in reducing the isoproterenol-stimulated secretion of amylase. These findings suggest that nitric oxide plays a role in secretion of amylase from parotid. Different affinity of lead acetate to interact with different nitric oxide synthases might be a reason for different effects on parotid amylase secretion observed in the presence or absence of secretion stimulant