title: Sensory receptors and their afferents in the caudal sympathetic nerve of the domestic duck.
abstract: The behavioural reactivity of the visceral receptors and their afferents in the caudal sympathetic nerve (part of synsacral sympathetic chain) of domestic duck (Anas platyrhynchos) was studied using electrophysiological techniques to examine their involvement in different physiological functions. In total, 114 single unit activities were recorded from the caudal sympathetic nerve of duck. Receptors were classified according to location: in the anal sphincter (32 units), in the mucous membrane of the cloaca (45 units), at the branching point of the blood vessels over the rectum and adjacent mesentery (10 units), at the base of the feather follicles in and around the vent (17 units), and in the ventral and lateral lower abdominal wall muscle (10 units). Both spontaneous and non-spontaneous receptors responded to mechanical stimuli; average frequency of discharge of non-spontaneous units being much higher. Most of these receptors were of the rapidly-adapting type. Only some receptors in the abdominal muscle layer, anal sphincter and mucous membrane of hind gut were of the slowly-adapting type. Some of the latter responded to intraluminal distension pressure. Except for responses to succinylcholine chloride by receptors in the abdominal wall muscles and some units in the external anal sphincter, mechanosensitive receptors were not responsive to chemical stimuli. The discharge rate of the receptors at the base of the feather follicles varied according to the strength of stimulus. Conduction velocity of the caudal sympathetic afferent fibres ranged from 2.5 to 45 m/sec.
mesh_terms: D000005:Abdomen / Q000294:innervation*; D000009:Abdominal Muscles / Q000294:innervation; D001003:Anal Canal / Q000294:innervation; D000818:Animals; D002988:Cloaca / Q000294:innervation; D004372:Ducks / Q000502:physiology*; D004594:Electrophysiology; D005241:Feathers / Q000294:innervation; D008643:Mesentery / Q000294:innervation; D009475:Neurons, Afferent / Q000502:physiology; D012007:Rectum / Q000294:innervation; D011984:Sensory Receptor Cells / Q000187:drug effects / Q000502:physiology*; D013564:Sympathetic Nervous System / Q000502:physiology*