Vasodilatation in the submaxillary gland of the rabbit

Abstract

SUMMARY1. In the rabbit, in contrast to the cat and dog, the vasodilatation and the secretion in the submaxillary gland which accompany parasympathetic nerve stimulation are correspondingly sensitive to atropine block.2. It is concluded that true vasodilator nerve fibres to the submaxillary gland exist in the chorda tympani nerve of the rabbit.3. The vasodilatation which follows sympathetic vasoconstriction in the submaxillary gland of the rabbit is small and variable. The possibility that this after-dilatation is due to an adrenergic neurotransmitter agent acting on fl-vascular receptors is discussed. INTRODUCTIONEvidence was presented (Bhoola, Morley, Schachter & Smaje, 1965), in accord with the view that vasodilator nerve fibres are present in the parasympathetic nerve supply to the cat's submaxillary gland. It was concluded that salivary kallikrein does not play a significant role in the vasodilatation produced by stimulation of the chorda-lingual nerve. Since the submaxillary gland of the rabbit, like that of the cat and dog, contains a kinin-releasing enzyme, and since most experiments on vascular regulation in the submaxillary gland have been made on the cat and dog, we decided to extend this study to the rabbit. We found, to our surprise, that both the secretion and the vasodilatation, which result from chordalingual nerve stimulation in the rabbit, in contrast to what is seen in the cat and dog, are equally sensitive to atropine blockade.Some of these results were presented to the Physiological Society (Morley, Schachter & Smaje, 1963

Distribution of prostaglandins E1, E2, F1α and F2α, in some animal tissues

“…Stimulation of chorda tympani nerve leads to vasodilatation in these glands in the dog, cat and rabbit (Morley, Schachter & Smaje, 1963;Bhoola, Morley & others, 1965;Schachter, 1966). The cause of this vasodilatation is in dispute.…”

Analysis of reflex responses in preganglionic parasympathetic fibres innervating submandibular glands of rabbits.

“…There is a possibility that each of these three kinds of neural information conveyed via the three types of preganglionic fibres control the physiological functions of the submandibular gland differentially because of the following notions. Although functional characteristics of a synaptic connexion between pre-and post-ganglionic fibres have not been studied yet in submandibular ganglions of rabbits, intracellular recordings from submandibular ganglions of rats revealed that about 75 % of the post-ganglionic fibres were connected with a single preganglionic fibre (Suzuki & Sakada, 1972;Lichtman, 1977), and the parasympathetic neural information is conducted to the three main effectors in submandibular glands such as the myoepithelial cells, blood vessels and secretary cells through submandibular ganglions in rabbits, cats and dogs (Morley, Schachter & Smaje, 1966;Emmelin et al 1968Emmelin et al , 1969Freitag & Engel, 1970;Garrett, 1977).…”

Secretion of kallikrein and its role in vasodilatation in the submaxillary gland

“…This suggestion extended Barcroft's (1914) view that functional vasodilatation was caused by the secretorv metabolic activity of the gland cells, by implicating kallikrein as the hitherto unidentified metabolic mediator of vasodilatation. The view that kallikrein released into the interstitial fluid during secretion was the physiological mediator of functional vasodilatation not only in the salivary glands, but also in sweat, pancreatic and other glands, has since been maintained by some workers (Hilton & Lewis, 1955 a, b;1956;Fox & Hilton, 1958;Hilton & Jones, 1963) and opposed by others (Bhoola, Morley & Schachter, 1962;Bhoola, Morley, Schachter & Smaje, 1965;Morley, Schachter & Smaje, 1966;Webster, 1966;Skinner & Webster, 1968;Schachter & Beilenson, 1967).…”