The Effect of Prolonged Stimulation on Afferent Activity of the Goat Carotid Body
The carotid body (CB) has a major role in the time-dependent increase in ventilation upon exposure to prolonged hypoxia, i.e., the process of ventilatory acclimatization to hypoxia (VAH). The presence of the CB is required for VAH to proceed normally (Forster et al., 1981; Smith et al., 1986). We have examined the role of the CB in awake goats subjected to isolated perfusion of the CB while the systemic circulation remains normoxic (Busch et al., 1985; Bisgard et al., 1986a, 1986b). In these studies time- dependent acclimatization occurred only if steady-state hypoxic blood was perfused into the isolated CB. It did not occur when the CB was perfused with hypercapnic blood. These data suggested that CB afferent activity increased in a time-dependent manner during hypoxic but not hypercapnic CB stimulation. Subsequent studies involving the direct measurement of CB afferent activity in anesthetized goats provided evidence that this was indeed the case (Nielsen et al., 1988; Engwall et al., 1988).
KeywordsCarotid Body Discharge Frequency Hypoxic Ventilatory Response Carotid Sinus Nerve Ventilatory Drive
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