Lactate does not activate the carotid body of Wistar rat

• Published in: Respiratory physiology & neurobiology 2021-03, Vol.285, p.103593-103593, Article 103593
• Main Authors: Spiller, Pedro F., da Silva, Melina P., Moraes, Davi J.A.
• Format: Article
• Language: English
• Subjects: Carotid body; Glomus cells; Petrosal ganglion and lactate; Whole cell patch clamp
• ISSN: 1569-9048; 1878-1519
• DOI: 10.1016/j.resp.2020.103593

•The carotid body's glomus cells are the primary sensors of hypoxia in mammals.•Lactate is a potential contributing mechanism for the hypoxia sensitivity of glomus cells from mice.•Lactate did not affect the outward currents, membrane conductance, and membrane potential of Wistar rats' glomus cells.•Lactate applied into carotid body did not activate the chemoreceptive petrosal neurons of in situ preparation of Wistar rats.•Carotid body of Wistar rat is not sensitive to lactate. The carotid body's glomus cells are the primary sensors of hypoxia in mammals. Previous studies suggested that the glomus cells' hypoxia sensitivity is mediated by lactate in mice. This molecule increases the intracellular [Ca2+] and induces exocytosis in glomus cells, activating the carotid sinus nerve (the axons of chemoreceptive petrosal neurons). On the other hand, how lactate affects the activity of carotid body of rats is still unknown. We hypothesized that lactate activates the carotid body of rats. In Wistar rats, we measured the changes in the electrical properties of isolated glomus cells and petrosal chemoreceptive neurons in in situ preparations in response to different concentrations of lactate. Superfusion of both physiological and supraphysiological concentrations of lactate did not affect the membrane conductance and potential of glomus cells. Moreover, lactate injected into the carotid body did not activate the anatomically and physiologically identified chemoreceptive petrosal neurons. We conclude that the carotid body of Wistar rats is not sensitive to lactate.