title: The effects of ischemia, lactic acid and hypertonic sodium chloride on phrenic afferent discharge during spontaneous diaphragmatic contraction.
abstract: In 9 sodium pentobarbital anaesthetized cats, 50 single-unit phrenic afferent recordings were determined during spontaneous ventilation, retrograde carotid arterial injection of lactic acid (LA, 0.1 N) and NaCl (5%), and a 2-min occlusion of the superior thoracic aorta. Fifty percent of the units had tonic low-frequency spontaneous discharge; 50% had phasic high-frequency discharge. Tonic fiber activity increased significantly with LA, NaCl and occlusion, while phasic fiber activity decreased in all 3 conditions. These results suggest that the diaphragm contains sensory endings sensitive to ischemia and extracellular metabolic changes.
mesh_terms: D000818:Animals; D002415:Cats; D003964:Diaphragm / Q000098:blood supply / Q000294:innervation*; D004576:Electromyography; D007511:Ischemia / Q000503:physiopathology; D007773:Lactates / Q000494:pharmacology; D019344:Lactic Acid; D009119:Muscle Contraction; D009413:Nerve Fibers, Myelinated / Q000502:physiology; D009475:Neurons, Afferent / Q000502:physiology; D010791:Phrenic Nerve / Q000502:physiology*; D012462:Saline Solution, Hypertonic / Q000494:pharmacology
chemical_list: D007773:Lactates; D012462:Saline Solution, Hypertonic; D019344:Lactic Acid