Cefaclor, a cephalosporin antibiotic, delays gastric emptying rate by a CCK-A receptor-mediated mechanism in the rat

1 Studies in vitro suggest that cephalosporin antibiotics release the gut h ormone cholecystokinin. Cholecystokinin is known to inhibit gastric emptyin g. Here we examine the effects of cefaclor on gastric emptying and intestin al motility. 2 Male Sprague-Dawley rats were fitted with gastric cannulas. Following a 3 -week recovery, the rate of gastric emptying of saline, peptone (4.5%) or c efaclor was determined after instillation into the gastric cannula, while i ntestinal transit was measured by using the propagation of arabic gum + cha rcoal mixture given intraduodenally. 3 Gastric emptying of saline was significantly delayed by the addition of c efaclor (3, 10, 30 or 100 mM). The CCK-A antagonist SR-27897B (1 mg kg(-1), i.p.) reversed the delay induced by 10 mM cefaclor, whereas the CCK-B anta gonist CI-988 (1 mg kg(-1), i.p.) had no significant effect. In capsaicin-t reated rats, 10 mM cefaclor emptied more rapidly than in vehicle-treated an imals. 4 Thirty-minute intestinal transit was increased at 30 and 100 mM of cefacl or, while the gastric acid secretion following cefaclor instillation was no different than the group which received saline. 5 The cephalosporin antibiotic cefaclor appears to be a potent stimulant of CCK release from gut endocrine cells, resembling the effects of peptone. C efaclor delays gastric emptying via capsaicin-sensitive afferent pathways, which involve CCK-A receptor interaction.