Abstract
Terbutaline (T), a beta-adrenergic agonist, was reported to attenuate the apnea reflex response to laryngeal water stimulation in newborn lambs (Pediatr. Res. 17:213, 1983). In order to delineate the mechanism of this drug action--central or via arterial chemoreceptors--laryngeal water administration was performed before and after bilateral carotid body denervation (CBD) in 4 term lambs, 2-4 weeks old. The apnea reflex response was expressed as % decrease in ventilation (Δ V) during water administration. Before CBD, T reduced Δ V significantly* (60 ± 11 to 23 ± 12%)+. This drug effect on Δ V was abolished by CBD (97 ± 4 vs 97 ± 3%). The effect of T on an index of "central respiratory drive" was studied by airway occlusion technique (P0.1) before and after CBD. T given before CBD increased P0.1 (4.5 ± 1.0 to 9.1 ± 1.5 cm H20)*. No change in P0.1 was seen when T was given after CBD (2.0 ± 0.4 vs 2.0 ± 0.2 cm H2O). Two sham operated lambs did not show the above described changes related to CBD. It is concluded that the attenuating effect of T on the apnea response to laryngeal water administration is mediated by the carotid bodies. An increase in "central respiratory drive" as determined by P0.1 was seen after T. This effect, however, also appears to be mediated by the carotid bodies. *p < 0.05, and +values are Mean ± SEM (Supported by MOD 1-739 and BRSG 21-25).
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Grogaard, J., den Abbeele, A., Krueger, E. et al. CAROTID BODIES MEDIATE THE ATTENUATING EFFECT OF BETA-ADRENERGIC AGONISTS ON APNEA REFLEX RESPONSE TO LARYNGEAL WATER ADMINISTRATION IN NEWBORN LAMBS. Pediatr Res 18 (Suppl 4), 407 (1984). https://doi.org/10.1203/00006450-198404001-01887
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DOI: https://doi.org/10.1203/00006450-198404001-01887