title: Carotid chemoreceptor discharge during epinephrine infusion in anesthetized cats.
abstract: It is known that during exercise there is an increase in plasma epinephrine. The purpose of the present investigation was to determine whether stimulation of carotid chemoreceptors by epinephrine is a direct effect or secondary to epinephrine-induced increases in arterial plasma [K+] and whole body CO2 production (VCO2). Chemoreceptor discharge was recorded from single fiber preparations of the carotid sinus nerves in anesthetized cats ventilated to a constant arterial PCO2 (PaCO2). Infusion of epinephrine (1 microgram.kg-1 x min-1) caused arterial [K+] to increase from a mean of 2.7 to 3.8 mM. VCO2 increased so that ventilation had to be increased by 60% to maintain PaCO2 constant. Mean chemoreceptor discharge increased by 50%, but this was no greater than would be predicted on the basis of the increases in arterial [K+] and VCO2. In a further group of experiments epinephrine was infused at 0.1 microgram.kg-1 x min-1 and produced no significant increase in chemoreceptor firing. These experiments provide no evidence for epinephrine having a direct effect on the carotid chemoreceptor.
authors: Laboratory of Applied Physiology, Sherrington School of Physiology, St. Thomas's Hospital, London, United Kingdom.
authors: R A
authors: RA
authors: Linton
authors: D M
authors: DM
authors: Band
authors: C B
authors: CB
authors: Wolff
mesh_terms: D000771:Anesthesia, Intravenous; D000818:Animals; D001774:Blood Chemical Analysis; D001784:Blood Gas Analysis; D002245:Carbon Dioxide / Q000378:metabolism; D002344:Carotid Body / Q000502:physiology*; D002415:Cats; D004837:Epinephrine / Q000008:administration & dosage / Q000378:metabolism*; D006863:Hydrogen-Ion Concentration; D007262:Infusions, Intravenous; D011188:Potassium / Q000097:blood; D012119:Respiration / Q000502:physiology
chemical_list: D002245:Carbon Dioxide; D011188:Potassium; D004837:Epinephrine