Effects of salbutamol and BRL 37344 on diastolic arterial blood pressure, plasma glucose and plasma lactate in rabbits |
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Authors: | M Reverte and J Moratinos |
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Institution: | Farmacología, Facultad de Medicina, Universidad de Salamanca, Av. Campo Charro s/n, 37007 Salamanca, Spain |
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Abstract: | Summary— The aim of this study was to investigate in rabbits the diastolic arterial blood pressure, plasma glucose and plasma lactate responses to salbutamol (a selective beta-2 adrenoceptor agonist) and BRL 37344 (a selective beta-3 adrenoceptor agonist) in comparison with CGP 12177 (a potent beta-1 and beta-2 adrenoceptor antagonist which also acts as a partial beta-3 agonist), isoprenaline (a non-selective beta-1, beta-2 and beta-3 adrenoceptor agonist) and adrenaline (a non-selective beta and alpha adrenoceptor agonist). All drugs were iv infused at the same dose: 0.3 μg/kg/min (30 min). In sodium pentobarbitone (40 mg/kg)-anasthetized animals none of these compounds altered diastolic arterial blood pressure. BRL 37344 (0.1, 0.3, 1 μg/kg/min) did not modify this parameter either. In conscious 24-h fasted rabbits, only adrenaline was able to increase plasma glucose levels. By contrast, under the same experimental conditions, salbutamol, isoprenaline and adrenaline, but not BRL 37344 or CGP 12177, induced a significant increase in plasma lactate levels. Finally, the salbutamol-mediated plasma lactate response was inhibited in the presence of clonidine (2 μg/kg/min, an alpha-2 adrenoceptor agonist), a drug considered to have opposite effects (stimulatory and inhibitory) on the adenylate cyclase system. In conclusion, these data suggest that only beta-2 adrenoceptor stimulation is able to increase plasma lactate levels, a response which is inhibited by alpha-2 adrenoceptor stimulation. |
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Keywords: | BRL 37344 salbutamol blood pressure plasma lactate plasma glucose rabbits |
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