Choline Acetylase in Normal and Denervated Salivary Glands

Nordenfelt, I.

doi:10.1113/expphysiol.1963.sp001639

Cited by 48 publications

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“…The right gland was denervated and the left one used as a control. In the rabbit the auriculotemporal nerve, which contains the postganglionic parasympathetic fibres, of the left parotid gland, was sectioned [Nordenfelt and Ohlin, 1958] and the right gland served as a control. The operations were carried out aseptically under pentobarbitone anaesthesia (cats) or pentobarbitone and ether (rabbits).…”

Section: Methodsmentioning

confidence: 99%

“…The synthesis and breakdown of ACh is known to decrease after section of the postganglionic parasympathetic nerves [Stromblad, 1955;Nordenfelt, 1963] and an attempt has been made to correlate these changes in ACh metabolism with the secretory activity during "degeneration secretion".…”

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confidence: 99%

“…These two glands were chosen mostly for technical reasons. Both glands have a fairly high rate of ACh synthesis [Nordenfelt, 1963]. The submaxillary gland of the cat where the "degeneration secretion" is most extensively studied, can be denervated postganglionically only partially, but it is possible to achieve a more complete denervation in the parotid gland of the rabbit.…”

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Acetylcholine Metabolism in Salivary Glands During the “Degeneration Secretion”

Nordenfelt

1964

Exp Physiol

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The synthesis and breakdown of ACh have been studied in the submaxillary gland of the cat and in the parotid gland of the rabbit during the "degeneration secretion", that is during the first days after postganglionic parasympathetic denervation.The decrease in the cholinesterase activity found in both glands cannot be the cause of the secretory activity. It might, however, increase and prolong the secretion in the rabbit's parotid gland.The "degeneration secretion" and the disappearance of choline acetylase activity seem to occur simultaneously, thus showing that the secretory activity and the degeneration of the nerve endings probably are closely related to each other. The findings suLpport the hypothesis that the secretion is caused by an increased liberation of ACh from the degenerating nerve endings.A TRANSIENT secretory activity has been observed in the parotid gland of the cat after postganglionic parasympathetic denervation [Emmelin and Stromblad, 1958]. It appears during the first 3 days after section of the auriculotemporal nerve and occurs in periods of varying length alternating with periods of secretory inactivity. A similar phenomenon has also been found in the submaxillary and sublingual glands of the cat after partial postganglionic parasympathetic denervation [Emmelin, 1962]. The flow of saliva in these glands is not periodic but fairly regular while it occurs, that is between about 18 and 60 hr. after the denervation. It is enhanced by eserine and abolished by a small dose of atropine or local anaesthetics injected into the gland. This type of secretory activity in the salivary glands has been assumed to be due to an increase of a normal leakage of acetylcholine (ACh) from the postganglionic nerve endings during the degeneration period. It has therefore been called "degeneration secretion" [Emmelin, 1962]. This secretory activity is to be distinguished from the " paralytic secretion" [Burgen and Emmelin, 1961]. The "degeneration secretion" has also been observed more recently in the submaxillary and parotid glands of the rabbit [Ohlin, 1963].The present investigation deals with the ACh metabolism in the salivary glands during the time of the "degeneration secretion". The synthesis and breakdown of ACh is known to decrease after section of the postganglionic parasympathetic nerves [Stromblad, 1955;Nordenfelt, 1963] and an attempt has been made to correlate these changes in ACh metabolism with the secretory activity during "degeneration secretion".Choline acetylase and cholinesterase activities have been studied in the submaxillary gland of cats and the parotid gland of rabbits during the first days after postganglionic parasympathetic denervation. These two glands were chosen mostly for technical reasons. Both glands have a fairly high 103

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Section: Methodsmentioning

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Acetylcholine Metabolism in Salivary Glands During the “Degeneration Secretion”

Nordenfelt

1964

Exp Physiol

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“…Stores of extranervous atrial acetylcholine have been reported by Lewartowski and Bielecki [1963]. In salivary glands the choline acetyltransferase is confined to the nerves [Nordenfelt, 1963;Ekstr6m and Holmberg, 1972a]. Here, the activity of the enzyme has been shown to depend on the secretory impulses to the gland [Nordenfelt, 1964;Ekstr6m and Holmberg, 1972b;Ekstr6m, 1973].…”

Section: Weightsmentioning

confidence: 96%

Choline Acetyltransferase in the Heart and Salivary Glands of the Rat After Physical Training

Ekström

1974

Exp Physiol

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After physical training of rats for 11-14 weeks both weight of atria and weight of ventricles were higher in relation to body weight than those of untrained controls. The capacity to synthesize acetylcholine, as judged by the activity ofcholine acetyltransferase, was increased in the atria of the trained rats, but the enzyme activity did not change in the ventricles. This result seems to support the concept of a high cholinergic activity as one cause of the low resting heart rate after training.Salivary glands are known to take part in thermo-regulation in rats. After the period of training increased submaxillary gland weight was found in relation to bodyweight, but two other major salivary glands were unchanged. Although the training seems to have caused increased secretory activity of the submaxillary gland, no changes in the activity of choline acetyltransferase were noticed.Increased cholinergic activity is one of the factors which has been suggested as responsible for the low heart rate observed after physical training [Herrlich, Raab and Gigee, 1960;Tipton and Taylor, 1965; Tipton, Barnard and Tharp, 1966]. Choline acetyltransferase is present both in the atria [Tucek, 1964;Ekstr6m, 1970] and ventricles [Ekstr6m, 1970] of the rat's heart. In the present study the effect on the synthesis of acetylcholine in these two parts has been determined after prolonged physical training. Since it is known that the salivary glands of the rat take part in thermoregulation and the rats were found to spread saliva onto their body surfaces after the runuing sessions, choline acetyltransferase activity was estimated also in the parotid and submaxillary glands. METHODSMale rats, initially about 3 months old, of a Sprague-Dawley strain bred at this Institute were exercised in a motor driven rotating drum six to seven times weekly. The speed and running period were slowly increased. At the beginning of the 7th week the rats ran at 1500 m/hr for 1 hr/day. This training program was then continued until the experiment was finished 4 to 7 weeks later. Before and after the training sessions a film of plastic (Nobecutan, Bofors) was sprayed on to the feet of the animals. To prevent the rats from sliding a plate of metal was built into the drum. When the tail or the back was in contact with this plate the rats were electrically stimulated. Some of the rats were conditioned in the respect that the mere touch of the plate caused them to run again, although no electrical stimulation had occurred. However, during the weeks of exercise many rats had to be abandoned. In spite of the electrical stimulation some of them refused to run; this was especially seen in the first weeks of exercise. Some rats got swollen legs or injured their digits.The experimental rats were housed together with their respective control litter mates. Food and water were given ad libitum. Body weights were measured at the start and at the end of the experimental period; at the end the body lengths were also 73

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“…DURING an investigation of the choline acetylase activity in salivary glands of the cat [Nordenfelt, 1963] preganglionic parasympathetic denervation of the parotid gland was achieved by destruction of the tympanic plexus [Stromblad, 1955]. The results obtained after this parasympathetic denervation were inconsistent, and it was also regularly observed that the nictitating membrane was relaxed on the same side as the denervated parotid, indicating that sympathetic fibres to the membrane were severed.…”

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