Analysis of Chemoreceptor Responses to Tachykinins in Rats, Cats, and Rabbits
Substance P (SP) belongs to a family of peptides called tachykinins. It has been proposed that SP acts as a sensory transmitter or modulator in the peripheral nervous system1. The carotid body, a sensory organ that detects changes in arterial oxygen, contains SP-like immunoreactivity and may participate in chemoreception2. Neuropharmacological studies on the cat carotid bodies have shown that exogenous SP augments the sensory discharge of the in vivo 2,3 and in vitro 4 preparations. Furthermore, antagonists specific to tachykinin peptides prevent the sensory excitation produced by hypoxia, but not that caused by CO2 5. These observations suggest that a tachykinin peptide, perhaps SP, is necessary for the hypoxic excitation of the carotid body. If SP is important in carotid body chemo- reception: (a) it should be present in the glomus tissue of species other than cats; and (b) like hypoxia, chemoreceptor responses to exogenous SP should be excitatory across species. In the present study, we tested these possibilities on rats and the results were compared with cats and rabbits.
KeywordsCarotid Body Tachykinin Receptor Hypoxic Challenge Carotid Chemoreceptor Chemoreceptor Activity
Unable to display preview. Download preview PDF.
- 1.B. Pernow, Substance P, Pharmacol. Rev. 35:85 (1983).Google Scholar
- 3.D. S. McQueen, Effects of substance P on carotid chemoreceptor activity in the cat, J. Physiol. (Lond.) 302:31 (1980).Google Scholar
- 5.N. R. Prabhakar, J. Mitra, and N. S. Cherniack, Role of substance P in hypercapnic excitation of carotid chemoreceptors, J. Appl. Physiol. 63:2418 (1987).Google Scholar
- 8.N. R. Prabhakar and N. S. Cherniack, Importance of tachykinin peptides in hypoxic ventilatory drive, in: “Chemoreceptors and Reflexes in Breathing,” S. Lahiri, R. E. Forster II, R. O. Davies, and A. I. Pack, eds., Oxford Press, New York (1988).Google Scholar
- 9.D. Regoli, G. Drapeau, S. Dion, and P. D. Or leans-Juste, Receptors for neurokinins in peripheral organs, in: “Substance P and Neurokinins,” J. L. Henry, R. Couture, A. C. Cuello, G. Pelletier, R. Quirion, and D. Regoli, eds., Springer-Verlag, New York (1987).Google Scholar