Responses in muscle afferent fibres of slow conduction velocity to contractions and ischaemia in the cat.

摘要: The aim of the study was to find out what extent muscle receptors with slowly conducting afferent fibres (group III and IV) are activated by muscular contractions moderate force, kind afferents could mediate pain ischaemic exercise. In chloralose-anaesthetized cats, impulse activity single units from triceps surae recorded dorsal root filaments during intact blood supply after occlusion artery. Two types responses were observed without ischaemia. One characterized sudden onset a graded response amplitude increasing force. most cases stretching also an effective stimulus. Units showing this behaviour labelled c.s.m (contraction-sensitive mechanical mechanism activation). other type had more delayed often outlasted exercise period; because unknown activation, c.s.x. proportion significantly higher amongst group than IV units. During comparable force c.s.x exhibited unchanged or decreased amplitude. Under these conditions another receptor (N, for nociceptive) which did not respond supply. Vigorous activations work only in receptors. majority 131 tested at all. These contraction-insensitive (c.i.) endings probably comprised different populations (nociceptors, thermoreceptors, low-threshold mechanoreceptors). It is concluded that various central nervous effects ischaemia known be due raised thin (e.g. cardiopulmonary adjustments, spinal locomotor reflexes) produced types. likely mediated N possess non-myelinated fibres.