Secretory Responses to Sympathetic Stimulation of the Cat's Salivary Glands in a State of Resting Secretion

Emmelin, N.; Gjörstrup, P.

doi:10.1113/expphysiol.1975.sp002326

Cited by 21 publications

(10 citation statements)

References 13 publications

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“…1975). Such an inhibitory action could be ruled out in the present experiments, and instead a slight transient increase of the ongoing parasympathetically produced fluid secretion was occasionally observed some minutes after injection of clonidine, and may have been due to augmented fluid secretion in response to activation of postjunctional aadrenoceptors (Emmelin & Gjorstrup 1975) or possibly to contraction of myoepithelial cells (Emmelin & Gjorstrup 1973). The results cannot with certainty distinguish between an a l -or a2-adrenoceptor effect, because of the high dose of clonidine, 10-30 pgkg, at which it was obtained; it is known from previous experiments that in the presence of a parasympathetic activity phenylephrine in lower doses causes fluid secretion from this gland (Gjorstrup 1977).…”

Section: Resultsmentioning

confidence: 57%

“…However, in the salivary glands a prejunctional inhibition of the parasympathetic nerves by the sympathetic as it can be seen in the gut at physiological stimulation frequencies (e.g. Gillespie & Khoyi 1977) seems physiologically not very likely because the two kinds of nerves are synergists; in fact parasympathetic augmentation of sympathetic activity is often necessary to obtain any sympathetic fluid secretory effect, and is particularly seen at low parasympathetic stimulation frequencies (Emmelin & Gjorstrup 1975, Gjorstrup 1977.…”

Section: Discussionmentioning

confidence: 99%

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Effects of some α‐adrenoceptor stimulating and blocking agents on the salivary amylase secretion in the rabbit

Gjörstrup

1984

Acta Physiologica Scandinavica

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In rabbits under urethane anaesthesia parotid secretion of fluid and amylase in response to electrical stimulation of the sympathetic and parasympathetic nerves was measured before and after injections of various agents acting on alpha-adrenoceptors. Amylase secretion in response to sympathetic nerve stimulation at 0.5 and 1 Hz was markedly reduced by clonidine, 0.5-30 micrograms/kg, in a dose related manner. The effect was not due to an altered responsiveness of the gland, since isoprenaline still caused a large release of amylase. Phenylephrine, 10 micrograms/kg, and prazosine, 300 micrograms/kg, had no effect on the sympathetically evoked amylase secretion. Yohimbine in a dose of 0.5 mg/kg increased the amylase output in response to sympathetic nerve stimulation at 0.5 Hz by 70%, while the response at 1 Hz, which is close to maximum for the gland, was not significantly increased. The fluid and amylase secretion produced by parasympathetic nerve stimulation at 1.5, 5.0 and 10 Hz remained unchanged after clonidine, 1.0-30 micrograms/kg, or yohimbine 0.5 mg/kg. In rabbits provided with chronic parotid fistulae fluid and amylase secretion were studied after injections of clonidine, 30 micrograms/kg, and yohimbine, 1 mg/kg. In the conscious animal clonidine reduced not only amylase but also fluid secretion, by around 50 and 30%, respectively, indicating an effect on the activity in both the sympathetic and parasympathetic secretory nerves. Yohimbine increased the output of amylase during feeding, seen as an increased mean output of amylase due to an increased concentration of amylase in the saliva, while fluid secretion remained unchanged. The various experiments suggest that amylase secretion in response to sympathetic activation may be influenced by prejunctional control of transmitter release via alpha-2-adrenoceptors, and that this control may be of physiological significance. Parasympathetically evoked secretion does not seem to be under the influence of a similar control.

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Section: Resultsmentioning

confidence: 57%

Section: Discussionmentioning

confidence: 99%

Effects of some α‐adrenoceptor stimulating and blocking agents on the salivary amylase secretion in the rabbit

Gjörstrup

1984

Acta Physiologica Scandinavica

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“…Since the effect remaining after a-adrenoceptor block could be abolished by practolol it can be concluded that it was evoked via receptors of the &subgroup. Adrenoceptors of the Btype mediating salivary secretion in other species also belong to this subgroup (Thulin 1972, Gjorstrup 1975.…”

Section: Discussionmentioning

confidence: 99%

Effects of Sympathetic Nerve Stimulation in the Presence of a Slow Parasympathetic Secretion in the Parotid and Submaxillary Glands of the Rabbit

Gjörstrup

1977

Acta Physiologica Scandinavica

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Sympathetic secretory responses from the parotid and the submaxillary glands of the rabbit were studied; sympathetic excitation occurred either alone or during a slow parasympathetic background secretion, imitating the resting secretion normally present. The fairly rapid sympathetically evoked flow of saliva from the parotid gland was, in the background secretion, further increased and obtained at low frequencies, which at sympathetic stimulation alone were subthreshold. The effects, which could be repeated with sympathomimetic drugs in a pilocarpine induced secretion, were abolished by alpha and beta-adrenoceptor blockade in combination. The submaxillary gland gave a very scanty secretion on sympathetic excitation, the effects being mediated via beta-adrenoceptors. The responses were not increased in a background secretion but the main effect of sympathetic activation was to retard the salivary flow. The retardation was attributed to vasoconstriction accompanying sympathetic excitation. Eliminating the vasoconstrictor responses, while retaining the sympathetic secretory effects, did not reveal any increase of the sympathetic salivary responses in the submaxillary gland.

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“…An augmentation of secretion evoked by chorda-lingual nerve stimulation following additional sympathetic stimulation, as described in the cat and dog submaxillary and parotid glands [Emmelin and Gjorstrup, 1975;1976] was not observed in these experiments. But a reduction of the salivary flow was recorded, presumably secondary to a decrease of the glandular blood flow, since the retardation of the salivary flow vanished when the sympathetic vasoconstriction had been abolished.…”

Section: Discussionmentioning

confidence: 53%

Secretory, Motor and Vascular Effects in the Sublingual Gland of the Rat Caused by Autonomic Nerve Stimulation

Templeton

Thulin

1978

Exp Physiol

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The influence of the autonomic nerves on sublingual glands of rats was studied. Stimulation of the chorda-lingual nerve evoked a lively flow of saliva and was also thought to contract the myoepithelial cells in the gland. Sympathetic nerve stimulation, on the other hand, usually evoked no secretion and did not cause any motor responses in the sublingual gland. The glandular blood flow was increased by chorda-lingual nerve stimulation, and this vasodilatation persisted also when atropine had been administered. Sympathetic nerve stimulation decreased the sublingual blood flow; this vasoconstrictor effect was mediated via activation of a-adrenoceptors.Rat salivary glands have been increasingly used to investigate the secretory mechanisms of water, electrolytes and organic substances in exocrine glands in vivo and in vitro [see Ohlin, 1966;Schneyer, Young and Schneyer, 1972;Young, 1973;Selinger, Eimerl, Savion and Schramm, 1974;Thulin, 1976]. The sublingual gland of the rat is considered to be a convenient system for comparative studies of secretion from serous and mucous cells since both cell types are present in the acini of this gland [Kim, Nasjleti and Han, 1972].The innervation pattern of the sublingual gland of the rat is well established morphologically. Thus, the autonomic nerve terminals which are present around the acini seem to be cholinergic and are in very close association with the parenchymal and myoepithelial cells [Snell and Garrett, 1957; Scott and Pease, 1959]. According to Norberg and Olson [1965] adrenergic nerve terminals are found only adjacent to the blood vessels and at a relatively long distance from the parenchymal and the myoepithelial cells, although it has been proposed that the mucous cells of the sublingual acini are sympathetically innervated [Fujiwara, Tanaka, Hattori and Honjo, 1966]. But no information is available concerning the influence of the autonomic nerves on different effector cells in the rat sublingual gland, although secretion elicited by different secretagogues such as methacholine, adrenaline and isoprenaline has been studied in this gland by Ohlin and Perec [1965]. Accordingly secretory and motor events in the sublingual gland resulting from nerve stimulation and the administration of drugs have now been studied. Observations on the glandular blood flow were also made. METHODSForty male Wistar rats (280-380 g), anaesthetized with chloralose (100 mg. kg-') administered via a cannulated femoral vein after induction with ether, were used. A tracheal tube was inserted. The sublingual duct was cannulated either on the right or on the left side with a glass 59

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Secretory Responses to Sympathetic Stimulation of the Cat's Salivary Glands in a State of Resting Secretion

Cited by 21 publications

References 13 publications

Effects of some α‐adrenoceptor stimulating and blocking agents on the salivary amylase secretion in the rabbit

Effects of some α‐adrenoceptor stimulating and blocking agents on the salivary amylase secretion in the rabbit

Effects of Sympathetic Nerve Stimulation in the Presence of a Slow Parasympathetic Secretion in the Parotid and Submaxillary Glands of the Rabbit

Secretory, Motor and Vascular Effects in the Sublingual Gland of the Rat Caused by Autonomic Nerve Stimulation

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