Influence of adrenoceptor agonists and antagonists on fluid secretion in small bowel obstruction.
OBJECTIVE
To investigate the importance of adrenoceptors on fluid losses in small bowel obstruction.


METHODS
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.


CONCLUSIONS
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.
Nellgård
P
P
Department of Anesthesiology and Intensive Care, Sahlgren's Hospital, Göteborg University, Sweden.
Bojö
L
L
Jönsson
A
A
Cassuto
J
J
D000322:Adrenergic Agonists / Q000494:pharmacology*; D018674:Adrenergic Antagonists / Q000494:pharmacology*; D000420:Albuterol / Q000494:pharmacology; D000704:Analysis of Variance; D000818:Animals; D001834:Body Water / Q000378:metabolism*; D003000:Clonidine / Q000494:pharmacology; D007415:Intestinal Obstruction / Q000378:metabolism*; D007421:Intestine, Small / Q000187:drug effects* / Q000378:metabolism*; D007579:Jejunal Diseases / Q000378:metabolism; D008297:Male; D008790:Metoprolol / Q000494:pharmacology; D010656:Phenylephrine / Q000494:pharmacology; D011224:Prazosin / Q000494:pharmacology; D011294:Prenalterol / Q000494:pharmacology; D051381:Rats; D017207:Rats, Sprague-Dawley; D015016:Yohimbine / Q000494:pharmacology
D000322:Adrenergic Agonists; D018674:Adrenergic Antagonists; D010656:Phenylephrine; D015016:Yohimbine; D008790:Metoprolol; D011294:Prenalterol; D003000:Clonidine; D000420:Albuterol; D011224:Prazosin