Course and severity of postpartum metritis cases following antibiotic and PGF2α administration in postpartum metritis cows infected with BoHV-4.

Forty cows between day 1 and day 21 post-calving were examined for the presence of postpartum metritis in a dairy herd that had recently experienced an increase in metritis and that had previously tested positive against bovine herpes virus 4 (BoHV-4) by various methods. Antibodies against BoHV-4 were detected in sera from 15 of 22 cows. For the virological study, uterine swab samples of 22 cows with metritis were used and tested for BoHV-4 using polymerase chain reaction (PCR), virus isolation (VI), and immunofluorescence techniques. Twenty-two point seven per cent (5/22) of the vaginal discharge samples obtained from cows with metritis were found positive for BoHV-4 DNA by PCR. All of these samples were also positive in VI and/or immune fluorescence assay (IF). Swab samples were also tested for bacteria. Empirical therapy with a broad spectrum antibiotic (oxytetracycline) was administrated, pending culture and antibiotic sensitivity result. All cows with puerperal metritis or clinical metritis (CM) were treated with intra-uterine (i.u.) administration of oxytetracycline and with intramuscular (i.m.) injections of dinoprost tromethamine (PGF(2)α) for three consecutive days. Concurrently, with the administration of oxytetracycline and PGF(2)α, cows with a rectal temperature >39.5°C received an additional treatment with oxytetracycline (i.m) for three consecutive days. According to the antibiotic test result, on day 3 after the last oxytetracycline and PGF(2)α administrations, all cows were treated with a combination of amoxicillin and clavulanic acid (i.u.) for three consecutive days. All cows with metritis and that were positive for BoHV-4 recovered clinically after the administration of antibiotic and PGF(2)α. In conclusion, postpartum metritis cases in cows infected BoHV-4 recovered clinically following early diagnosis and prolonged treatments with a combination of antibiotics and PGF(2)α.

Identification of a 5-hydroxytryptamine (5-HT2) receptor on guinea pig small intestinal crypt cells.

Radioligand labeling of [3H]ketanserin was examined in suspensions of dispersed guinea pig small intestinal mucosal cells prepared by modification of the EDTA-chelation method described by M. M. Weiser (J. Biol. Chem. 248: 2536-2541, 1973). Preferential incorporation of [3H]thymidine was used to confirm that suspensions were enriched in crypt cells. At 25 degrees C, binding of [3H]ketanserin to dispersed enterocytes was rapid, maximal by 5 min, saturable (dissociation constant = 1.5 nM), 65 +/- 5% specific, stable, and reversible. The maximal number of binding sites per cell was 92,000 (range 86,000-105,500). Binding was temperature dependent, with maximal binding at 37 degrees C, and was inhibited by 5-hydroxytryptamine (5-HT) (half-maximal inhibition of [3H]ketanserin binding observed in response to 1 microM 5-HT) and ketanserin (half-maximal inhibition of [3H]ketanserin binding observed in response to 1 nM ketanserin) but not by the 5-HT1P antagonist N-acetyl-5-hydroxytryptophyl 5-hydroxytryptophan amide (5-HTP-DP) or the 5-HT3 antagonist 3-tropanyl-indole-3-carboxylate methiodide (ICS-205-930). The second messenger system coupled to the putative mucosal 5-HT2 receptor was examined. 5-HT stimulated a concentration-dependent production of inositol 1,4,5-trisphosphate (IP3) in the dispersed enterocytes. This was maximal at 1 min and was inhibited in a concentration-dependent manner by ketanserin. 5-HTP-DP and ICS-205-930 had no effect on 5-HT-stimulated production of IP3. These data provide evidence for the existence of a mucosal 5-HT2 receptor located on guinea pig small intestinal crypt cells.

Beta-adrenoceptors on duodenal mucosal cells mediate venous serotonin release.

We have previously documented predominant intraluminal release of serotonin (5-HT) following activation of muscarinic receptors on enterochromaffin cells. Gronstad et al. reported that portal venous release of 5-HT in response to vagal stimulation was mediated by beta-adrenergic receptors. The purpose of this study was to determine whether 5-HT release induced by the beta-adrenergic agonist, isoproterenol, is mediated by enteric nerves or is a direct action at the enterochromaffin cell level. We mounted rabbit duodenal mucosal sheets stripped of muscularis in modified Ussing chambers and measured release of 5-HT in response to 10(-5) M isoproterenol, in the presence and absence of the neural conduction blocker tetrotoxin, 10(-6) M. Serotonin was measured in the buffer bathing the mucosal and submucosal surfaces by HPLC. In the presence of isoproterenol, total (mucosal and submucosal) 5-HT release (21.0 +/- 4.9 ng/cm2/45 min) was significantly (P less than 0.05) greater than that in untreated controls (7.8 +/- 2.7 ng/cm2/45 min); release was predominantly toward the submucosal surface. In the presence of tetrodotoxin alone, net 5-HT release was significantly (P less than 0.05) increased to 12.8 +/- 2.8 ng/cm2/45 min. In tetrodotoxin-treated mucosa, isoproterenol increased 5-HT release to 28.6 +/- 5.3 ng/cm2/45 min which was significantly greater (P less than 0.05) than that with tetrodotoxin alone. Since 5-HT release was increased even in the presence of neural blockade, these results suggest that activation of beta-adrenergic receptors on or near enterochromaffin cells induces release of 5-HT predominantly toward the submucosal surface.