Title: Effects of CO<sub>2</sub>- HCO 3 − on catecholamine efflux from cat carotid body
Abstract: Iturriaga, Rodrigo, and Julio Alcayaga. Effects of CO 2 -[Formula: see text]on catecholamine efflux from cat carotid body. J. Appl. Physiol. 84(1): 60–68, 1998.—Using a chronoamperometric technique with carbon-fiber microelectrodes and neural recordings, we simultaneously measured the effects of the following procedures on catecholamine efflux (ΔCA) and frequency of chemosensory discharges ( f x ) from superfused cat carotid body: 1) the addition of CO 2 -[Formula: see text]to Tyrode solution previously buffered with N-2-hydroxyethylpiperazine- N′ -2-ethanesulfonic acid, maintaining pH at 7.40; 2) hypercapnia (10% CO 2 , pH 7.10); 3) hypoxia ([Formula: see text] h ≈ 40 Torr) with and without CO 2 -[Formula: see text]; and 4) the impact of several boluses of dopamine (DA; 10–100 μg) on hypoxic and hypercapnic challenges. With CO 2 -[Formula: see text], hypoxia increased f x which preceded ΔCA increases, whereas hypercapnia raised f x but did not consistently increase ΔCA. Repeated stimuli induced similar f x increases, but attenuated ΔCA. After DA, hypoxia produced larger ΔCA, which preceded chemosensory responses. Without CO 2 -[Formula: see text], hypoxia produced a similar pattern of ΔCA and f x responses. Switching to Tyrode solution with CO 2 -[Formula: see text]at pH 7.40 raised f x but did not increase ΔCA. With CO 2 -[Formula: see text]and after DA, hypoxic-induced ΔCAs were larger than in its absence. Results suggest that DA release is not essential for chemosensory excitation.
Publication Year: 1998
Publication Date: 1998-01-01
Language: en
Type: article
Indexed In: ['crossref', 'pubmed']
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Cited By Count: 15
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