Chemoreceptor response to hypoxia and hypercapnia in catecholamine depleted rabbit and cat carotid bodies in vitro
- 22 Downloads
The response of single chemoafferent fibres to hypoxic and hypercapnic stimulation was studied in vitro under different experimental conditions: 1. control, 2. 24 h after reserpinization (5 mg/kg iv) and 3. 18 h after iv injection of α-methyl-p-tyrosine (100 mg/kg in the rabbit, and 1. control and 2. 24 h after reserpinization (5 mg/kg ip) in the cat. The spontaneous activity was decreased by monoamine depletion. The amplitude of the response to hypoxia and to hypercapnia was decreased by reserpinization in the rabbit and in the cat, the change being less marked in the latter species. Similarly, treatment with·α-methyl-p-tyrosine decreased the ability of chemoreceptors to respond to hypoxia and hypercapnia and, in a few instances, these receptors could only be excited by superfusion of nitrogencquilibrated medium. These results emphasize to possible role of monoamine, and particularly dopamine, in modifying the sensitivity of arterial chemoreceptors to their natural stimuli.
Key wordsRabbit Cat Chemoreceptor Reserpine α-Methyl-p-tyrosine
Unable to display preview. Download preview PDF.
- Docherty RJ, McQueen DS (1979) The effects of acetylcholine and dopamine on carotid chemosensory activity in the rabbit. J Physiol (Lond) 288:411–424Google Scholar
- Fidone SJ, Sato A (1969) A study of chemoreceptor and baroreceptor A and C fibres in the cat carotid body. J Physiol (Lond) 205:527–548Google Scholar
- Leitner L-M, Roumy M, Ruckebusch M, Sutra A (1986) Monoamines in the rabbit carotid body: effects of reserpine, sympathectomy and carotid sinus nerve section. Pflügers Arch, in pressGoogle Scholar
- Llados F, Zapata P (1978) Effect of dopamine analogues and antagonists on carotid body chemosensors in situ. J Physiol (Lond) 274:487–500Google Scholar
- Zapata P (1975) Effects of dopamine on carotid chemo- and baroreceptors in vitro. J Physiol (Lond) 244:235–251Google Scholar