Watson CS, White SE, Homan JH, Fraher L, Brien JF, Bocking AD. The adenosine A(1)-receptor antagonist 8-CPT reverses ethanol-induced inhibition of fetal breathing movements.
J Appl Physiol (1985) 1999;
87:1333-8. [PMID:
10517760 DOI:
10.1152/jappl.1999.87.4.1333]
[Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Administration of either ethanol or adenosine inhibits fetal breathing movements (FBM), eye movements, and low-voltage electrocortical activity (LV ECoG). The concentration of adenosine in ovine fetal cerebral extracellular fluid increases during ethanol-induced inhibition of FBM. The purpose of this study was to determine the effect of a selective adenosine A(1)-receptor antagonist, 8-cyclopentyltheophylline (8-CPT) on the incidence of FBM during ethanol exposure. After a 2-h control period, seven pregnant ewes received a 1-h intravenous infusion of ethanol (1 g/kg maternal body wt), followed 1 h later by a 2-h fetal intravenous infusion of either 8-CPT (3.78 +/- 0.08 microg. kg(-1). min(-1)) or vehicle. Ethanol reduced the incidence of FBM from 44.0 +/- 10.4 to 2.7 +/- 1.3% (P < 0.05) and 51.2 +/- 7.6 to 11.9 +/- 5.0% (P < 0.05) in fetuses destined to receive 8-CPT or vehicle, respectively. In the vehicle group, FBM remained suppressed for 7 h. In contrast, during the first hour of 8-CPT infusion, FBM returned to baseline (31 +/- 11%) and was not different from control throughout the rest of the experiment. Ethanol also decreased the incidence of both low-voltage electrocortical activity and eye movements, but there were no differences in the incidences of these behavioral parameters between the 8-CPT and vehicle groups throughout the experiment. These data are consistent with the hypothesis that adenosine, acting via A(1) receptors, may play a role in the mechanism of ethanol-induced inhibition of FBM.
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