Protein Secretion and the Identification of Neurotransmitters in the Isolated Pig Lacrimal Gland
The lacrimal gland is innervated with autonomic nerves which regulate protein secretion (Bothelho, 1964; Bromberg, 1981). Immunohistochemical studies have demonstrated the distribution of adrenergic, cholinergic and peptidergic nerves in the lacrimal of several animal species (Dartt et al, 1984; Ehinger, 1964; Lunberg et al, 1980). The known putative neurotransmitters released by these nerves include acetylcholine (ACh), noradrenaline (NA), vasoactive intestinal polypeptide (VIP), neuropeptide Y (NPY) and Substance P. Exogenous application of some of these putative neurotransmitters can stimulate protein secretion (Dartt et al, 1984; Hussain and Singh, 1988; Dartt, 1989) and exert vasodilatory effects in the lacrimal (Lunberg et al, 1980). However, studies involving protein secretion and the distribution of peptidergic and aminergic nerves in the pig lacrimal gland has long been neglected despite its similarity to human. This study investigates the effects of exogenous application of 5-hydroxytryptamine (5-HT), dopamine, VIP and NPY on total protein output and the distribution of nerve fibres containing neuropeptides including NPY, VIP and amines such as 5-HT and dopamine in the isolated pig lacrimal gland.
KeywordsAcinar Cell Vasoactive Intestinal Polypeptide Lacrimal Gland Immunoreactive Nerve Dopamine Beta Hydroxylase
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