Degeneration secretion from parotid glands after section of the auriculotemporal nerves at different levels.

1. In cats under ether or hexobarbitone anaesthesia the auriculotemporal nerve was cut near the parotid gland on one side and 12-20 mm more proximally on the other. After 22-64(1/2) hr the cats were anaesthetized with chloralose and the parotid ducts cannulated. Degeneration secretion of saliva which appears after post-ganglionic parasympathetic denervation was found to start 2-5(1/2) hr later in the gland denervated proximally than in that denervated distally. It ceased, on the other hand, later in the former than in the latter gland.2. Before degeneration secretion had started spontaneously it could be provoked by intravenous injection of acetylcholine, methacholine, carbachol or eserine and the effect was more pronounced on the gland denervated distally. When it had ceased spontaneously it could also be provoked, and the effect on the other gland was now more marked.3. Earlier it has been assumed that while a nerve is degenerating there is a period when the nerve endings are unable to retain in a normal way acetylcholine still being synthesized. It is now suggested that this period starts later after proximal than after distal denervation because more of the material required for the normal function of the endings is available in a long piece than in a short piece of nerve.