| Popis: |
OBJECTIVES To investigate the importance of adrenoceptors on fluid losses in small bowel obstruction. DESIGN Evaluation of the effects of adrenergic agonists and antagonists on in-vivo net fluid secretion in chronic small bowel obstruction in rats. METHODS Net fluid transport in a jejunal segment was continuously registered in vivo after 18 h of mechanical obstruction of the small bowel in anaesthetized rats. The effect on net fluid transport of adrenoceptor agonists and antagonists and of isotonic saline was quantified. RESULTS Clonidine, an alpha 2-agonist, had a significant (P < 0.05) anti-secretory effect, while yohimbine, an alpha 2-antagonist, significantly (P < 0.05) increased net fluid secretion. Phenylephrine, an alpha 1-agonist, and prazosin, an alpha 1-antagonist, lacked significant effects on net fluid transport. Similarly, prenalterol, a beta 1-agonist, and metoprolol, a beta 1-antagonist, had no significant effect on the net fluid transport. The beta 2-agonist salbutamol significantly (P < 0.001) decreased net fluid secretion, while the beta-antagonist propranolol significantly (P < 0.001) decreased net fluid secretion. CONCLUSION Activation of alpha 2-adrenoceptors and blockade of beta 2-adrenoceptors significantly reduce net fluid secretion in small bowel obstruction. Results also demonstrate a continuous stimulatory effect on fluid secretion mediated by beta 2-receptors and a continuous inhibitory effect mediated by alpha 2-receptors. |
