摘要:

Roger, T.&Ruckebusch, Y. Pharmacological modulation of postprandial colonic motor activity in the pony.J. vet. Pharmacol. Therap.10, 273–282.The contractile activity of the equine large intestine exhibited a biphasic response to feeding: enhancement of migrating complexes passing along the colon and an increase of 50% in cyclic variations in smooth muscle at intervals of 20 min on the left ventral colon for a period of 5 to 7 h postfeeding. The cholinergic agonist, bethanechol (50 μg/kg subcutaneously), induced both the migrating complexes and the cyclic variations at intervals of 10–15 min. In contrast, the intra‐arterial infusion of PGF2a(3 μg/kg/min) increased the contractile activity during infusion, but without inducing distinct patterns of activity. Atropine but not indomethacin or flunixin pre‐treatment prevented the effects of postprandial, cholinergic and PGF2astimulation of colonic motility, suggesting that the gastrocolonic reflex involved mainly cholinergic stimulation of the caecum and replicated colon, including the prostaglandin F2aexcitator

ISSN:0140-7783    

DOI:10.1111/j.1365-2885.1987.tb00102.x

出版商:Blackwell Publishing Ltd    

年代:1987

数据来源: WILEY

摘要:

Ravis, W.R., Duran, S.H., Pedersoli, W.M.&Schumacher, J. A pharmacokinetic study of phenobarbital in mature horses after oral dosing.J. vet. Pharmacol. Therap.10, 283–289.The pharmacokinetics of phenobarbital were determined in six mature horses after a single oral dose. Horses were administered a 5.5 mg/kg of body weight oral dose of phenobarbital tablets. Based on the combined evaluation of i.v. and oral results, phenobarbital displayed two‐compartment pharmacokinetics in the horse with a terminal half‐life of 19.0 ± 4.4 (mean ± SD) h. This half‐life is considerably shorter than those reported for dogs and humans. The steady‐state volume of distribution(Vdss/F) and the total body clearance(Cl1/F)of phenobarbital were 0.753 ± 0.115 1/kg and 27.9 ± 9.2 ml/h/kg, respectively. The average extent of oral absorption was 101% with a range of 76 to 124% among the six horses. Examination of the absorption kinetics demonstrated a biphasic absorption process in four horses with a rapid absorption followed by a slower absorption phase. The mean residence time(MRT)was 36.9 ± 4.1 h and the mean residence time for oral absorption(MRTabs) was 11.3 h. Based on the results of the present study, an oral dosing regimen of 11 mg/kg of body weight every 24 h can

ISSN:0140-7783    

DOI:10.1111/j.1365-2885.1987.tb00103.x

出版商:Blackwell Publishing Ltd    

年代:1987

数据来源: WILEY

摘要:

Steffey, E.P., Hodgson, D.S., Dunlop, C.I., Miller, M.F., Woliner, M.J., Heath, R.B.&Grandy, J. Cardiopulmonary function during 5 hours of constant‐dose isoflurane in laterally recumbent, spontaneously breathing horses. J. vet. Pharmacol. Therap.10, 290–297.Hemodynamic and respiratory effects of 5 h of unvarying 1.57%, end‐tidal (1.2 MAC) isoflurane in O2 anesthesia were characterized in ten left laterally recumbent horses. Compared to base line values at 30 min of constant dose isoflurane, cardiac output, hematocrit, total plasma solids,PaC02, and peak inspired gas flow progressively and significantly(P<0.05) increased over the course of study. Arterial blood pressure increased(P<0.05) during the first 2 h of constant dose of isoflurane then decreased and remained near base line values. Inspiratory time progressively decreased with time of anesthesia. All horses recovered from anesthesia uneventfully within 1 h of termination of isofl

ISSN:0140-7783    

DOI:10.1111/j.1365-2885.1987.tb00104.x

出版商:Blackwell Publishing Ltd    

年代:1987

数据来源: WILEY

摘要:

Craig, A.M., Blythe, L.L., Appell. L.H.&Slizeski, M.L. Evaluation of the potential for interference by dimethyl sulfoxide (DMSO) in drug detection in racing animals.J. vet. Pharmacol. Therap.10, 298–304.Dimethyl sulfoxide (DMSO) had been postulated to be a ‘masking agent’ when used concurrently with therapeutic or prohibited drugs in racing animals. Eight drugs (flunixin, furosemide, caffeine, apomorphine, phenylbutazone, lidocaine, cocaine, and acepromazine maleate) were administered to six horses singly and with concurrent intravenous DMSO. Urine samples were analyzed for the presence of the drugs and/or their metabolites by thin layer chromatography. Direct comparison of thin layer chromatograms of extracts of positive urine samples with and without DMSO verified that DMSO did not interfere with the detection of these

ISSN:0140-7783    

DOI:10.1111/j.1365-2885.1987.tb00105.x

出版商:Blackwell Publishing Ltd    

年代:1987

数据来源: WILEY

摘要:

Bogan, J., Benoit, E.&Delatour, P. Pharmacokinetics of oxfendazole in goats: a comparison with sheep. J. vet. Pharmacol. Therap.10, 305–309.In goats, there was a linear correlation of area under the plasma concentration–time curve(AUC)with dose in the range 0–20 mg/kg as single dosages of oxfendazole (OFZ). The bioavailability of OFZ after oral administration was lower in goats than in sheep. The repetition of three administrations at 24 h intervals produced significant increase in theAUCin comparison with a single administration equivalent to the total dosage (1 × 5.0 and 3 × 1.7 mg/kg). Infection withO. circumcinctaproduced a 33% decrease in the bioavailability

ISSN:0140-7783    

DOI:10.1111/j.1365-2885.1987.tb00106.x

出版商:Blackwell Publishing Ltd    

年代:1987

数据来源: WILEY

摘要:

Roger, T.&Ruckebusch, Y. Colonic α2‐adrenoceptor‐mediated responses in the pony. J. vet. Pharmacol. Therap.10, 310–318.The motor responses of the caecum and colon to stimulation of α2‐adrenoceptors by xylazine and detomidine at the recommended dose levels of 0.6 and 0.1 mg/kg were investigated in three ponies. The motor changes of the left ventral colon induced by continuous intra‐arterial infusion of a prostaglandin (PGF2α) were used to assess the relative inhibitory effects of xylazine and detomidine in a colic model. The administration of α2‐agonists inhibited the spiking activity on the whole of the large intestine for 20–30 min (xylazine) or 2–3 h (detomidine). However, the detomidine‐induced inhibition was preceded by a short period of increased smooth muscle basal tone as indicated by strain‐gauge force transducer measurements. This pattern of activity was neither reversed nor prevented by the administration of tolazoline (10 μg/kg/min) intra‐arterially. In contrast, inhibition of the colonic phasic and tonic motor activity by α‐adrenoceptor stimulation was reversed competitively by tolazoline. The intra‐arterial infusion of prostaglandin F2α(10 μg/kg/min) induced prolonged and sustained spiking activity that might be related to signs of mild colic. Detomidine, and to a lesser extent xylazine, relaxed the whole of the large intestine and this was accompanied by alleviat

ISSN:0140-7783    

DOI:10.1111/j.1365-2885.1987.tb00107.x

出版商:Blackwell Publishing Ltd    

年代:1987

数据来源: WILEY

摘要:

Stenberg, D., Salven, P.&Miettinen, M.V.J. Sedative action of the α2‐agonist medetomidine in cats.J. vet. Pharmacol. Therap.10, 319–323.Medetomidine, a novel α2‐agonist drug intended for small animal sedation, was injected intramuscularly at dose rates of 0.02, 0.06 and 0.18 mg/kg. Xylazine (3.0 mg/kg) and saline were used for comparison. The five treatments were tested in a Latin square design in five cats. Treatments differed significantly in three‐way analysis of variance, medetomidine inducing an increase in drowsiness with a corresponding decrease in both aroused waking and sleep determined by polygraphical criteria. The duration of effect was dose‐dependent. The effect of 0.18 mg/kg medetomidine was comparable to 3.0 mg/kg of xylazine. The drugs also induced

ISSN:0140-7783    

DOI:10.1111/j.1365-2885.1987.tb00108.x

出版商:Blackwell Publishing Ltd    

年代:1987

数据来源: WILEY

摘要:

Garg, R.C., Keefe, T.J.&Vig, M.M. Serum levels and pharmacokinetics of ticarcillin and clavulanic acid in dog following parenteral administration of Timentin®. J. vet. Pharmacol. Therap. 10, 324–330.The serum concentration‐time data for ticarcillin (TICAR) and clavulanic acid (CLA) following intravenous and intramuscular administration of Timentin® (TICAR, 50 mg/kg with CLA, 1.7 mg/kg) indicated that absorption of CLA following intramuscular injection and its overall elimination from the body was faster than that of TICAR. This is supported by comparison of certain pharmacokinetic parameters for TICAR and CLA. These include the shorter value ofTmaxfor CLA (11.45 ± 1.60 min) than that for TICAR (29.93 ± 1.94 min) and significant variation in the elimination rate constants (0.183 ± 0.0018 min‐1for CLA vs. 0.0097 ± 0.0006 min‐1for TICAR) for the intravenous group of animals. The biological half‐life of CLA (approximately 39 min) was significantly shorter (P<0.01) than that of TICAR (approximately 73 min). In spite of initial faster absorption, the intramuscular bioavailability of CLA (65.02%) was less than that of TICAR (91.37%).Though the pharmacokinetic behaviour of TICAR and CLA is not similar, yet based on the therapeutically optimal concentrations of CLA and TICAR reached in serum, Timentin®at the dose used in the present study should be effective in treating most TICAR‐resistantEnterobacteriaceaeinfections in dogs. Timentin®is not likely to be effective in the treatment of infections caused by TICAR‐resistant pseudomonads, at the dose used

ISSN:0140-7783    

DOI:10.1111/j.1365-2885.1987.tb00109.x

出版商:Blackwell Publishing Ltd    

年代:1987

数据来源: WILEY

摘要:

Shoaf, S.E., Schwark, W.S.&Guard, C.L. The effect of age and diet on sulfadiazine/trimethoprim disposition following oral and subcutaneous administration to calves.J. vet. Pharmacol. Therap.10, 331–345.Thirty milligrams per kilogram of sulfadiazine/trimethoprim (SDZ/TMP, Trib‐rissen®) was given orally and subcutaneously (s.c.) to two groups of male, Hol‐stein calves. One group was fed milk‐replacer throughout the 13‐week period of the study while the second group was weaned onto a chopped grain‐fiber mixture when 5 weeks old. Serum and urine were assayed for concentrations of unchanged drug. Trimethoprim bioavailability, following oral administration at 1, 6 and 12 weeks of age, is higher in milk‐fed calves (non‐ruminants) than in grain‐fiber‐fed calves (ruminants); bioavailability decreases with increasing age in both groups of calves. Serum concentrations above 0.1 μg/ml (the level of sensitivity of the assay) could not be obtained in ruminating calves. The rate of SDZ absorption following oral administration, as determined by the Wagner‐Nelson method, was very slow in all the calves in this study with average half‐life values ranging from 8.2–12.67 h; absorption was slightly faster in ruminating calves. Absorption of SDZ is rate‐limiting and determines the biological half‐life of the drug; SDZ serum concentrations above 2 (μg/ml were maintained in all calves for at least 24 h. Following s.c. administration of Tribrissen®to 7‐and 13‐week‐old calves, urinary excretion patterns indicated that TMP was slowly released from the injection site; serum concentrations were below 0.1 μg/ml. In contrast, absorption of SDZ was very rapid; values for tmaxwere 1.5–1.8 h. The pharmacokinetic parameters for SDZ were calculated according to a one‐compartment open model; neither diet nor age had a significant effect on SDZ disposition following s.c. injection. Subcutaneous administration of 30 mg/kg Tribrissen®, b.i.d., may be the best therapeutic regimen; even though measure‐able concentrations of TMP cannot be achieved in the serum following a single s.c. dose, TMP concentrations should accumulate and, because of its sustained releas

ISSN:0140-7783    

DOI:10.1111/j.1365-2885.1987.tb00110.x

出版商:Blackwell Publishing Ltd    

年代:1987

数据来源: WILEY

ISSN:0140-7783    

DOI:10.1111/j.1365-2885.1987.tb00111.x

出版商:Blackwell Publishing Ltd    

年代:1987

数据来源: WILEY