The study was designed to qualitative and quantitative evaluation of the antinociceptive effect of metoclopramide and xylazine each alone or as a concomitant administration in mice. Adult albino Swiss mice weighing 20-30 mg used in all experiments. By using the hot plate test, the individual analgesic dose (ED50) of metoclopramide and xylazine detected depending on the up and down method. Isobolographic analysis used to evaluate the type of interaction between two drugs at the ratio 0.5:0.5 of individual ED50 for each drug at the level of antinociception effect. Simultaneously administration of the double dose of individual ED50 and low doses (sedative, non-analgesic doses) of both drugs, also evaluated at the level of central and visceral analgesia using a hot plate and writhing response test respectively. The individual ED50 of xylazine and metoclopramide was 10.8 and 25.6mg/kg IP respectively. A synergistic interaction at the level of analgesia explored between two drugs at ratio 0.5:0.5 which represented as decreased in ED50 of metoclopramide and xylazine by 58.75 and 58.15% respectively. The animal suffered from only slight sedation and docile. Simultaneously IP administration of xylazine and metoclopramide at double dose of ED50 for each drug-induced significant increase in latency time of thermal response, as well as a significant decrease in writhes number, which induced by acetic acid in comparison with control groups. The percentage of analgesia at sub analgesic doses of a concomitant administration of both drugs was 100% in comparison with each drug alone. These results suggested safe and good use of both drugs in veterinary medicine.

The efficacy of metoclopramide for preventing organophosphate insecticide-induced (diazinon) toxicosis was evaluated in 7~14 days old chicks. Injection of metoclopramide at 25 mg/kg, s.c. 15 min before diazinon increased the oral 24 h median lethal dose of the insecticide in the chicks by 80%. Metoclopramide alone inhibited the in vitro and in vivo plasma and whole brain cholinesterase activities of the chicks. Metoclopramide pretreatment at 100 mg/kg, s.c. reduced the extent of cholinesterase inhibition that was caused by diazinon (10 mg/kg, p.o.) in the plasma and whole brain by 24% and 7%, respectively. Diazinon at 10 mg/kg, p.o. produced signs of cholinergic toxicosis in the chicks, and these signs included salivation, lacrimation, gasping and convulsions within 2 h, and the 2-h and 24-h lethalities were 88 and 100%, respectively. Metoclopramide at the dose rates of 12.5, 25, 50, 100 and 200 mg/kg, s.c. given 15 min before diazinon (10 mg/kg, p.o.) variably decreased the occurrence of toxic manifestations in the chicks. The highest dose of metoclopramide (200 mg/kg, s.c.) reduced the 2-h and 24-h lethality of diazinon to 75% each and it reduced the overall toxicity score of diazinon by 32%. The data suggest that metoclopramide pretreatment only partially protected chicks against the acute toxicity of diazinon.

Background: Metoclopramide is a dopamine D2-receptor antagonist used as an antiemetic and gastroprokinetic agent in man and animals. The drug causes sedation as a side effect in man. Such a sedative action of metoclopramide has not been documented in the chicken as the drug is not used clinically in this species. The present study examines the central nervous system depressant effects of metoclopramide in 7-14 days old broiler chicks.

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Plasma and brain cholinesterase activities were determined in three wild bird species to assess their exposure to organophosphate and carbamate insecticides which are used in agriculture and public health. In the present study, we used an electrometric method for measurement of cholinesterase activities in the plasma and whole brain of three indigenous wild birds commonly found in northern Iraq. The birds used were apparently healthy adults of both sexes (8 birds/species, comprising 3–5 from each sex) of quail (Coturnix coturnix), collard dove (Streptopelia decaocto) and rock dove (Columba livia gaddi), which were captured in Mosul, Iraq. The mean respective cholinesterase activities (Δ pH/30 minutes) in the plasma and whole brain of the birds were as follows: quail (0.96 and 0.29), collard dove (0.97and 0.82) and rock dove (1.44 and 1.42). We examined the potential susceptibility of the plasma or whole brain cholinesterases to inhibition by selected insecticides. The technique of in vitro cholinesterase inhibition for 10 minutes by the organophosphate insecticides dichlorvos, malathion and monocrotophos (0.5 and 1.0 µM) and the carbamate insecticide carbaryl (5 and10 µM) in the enzyme reaction mixtures showed significant inhibition of plasma and whole brain cholinesterase activities to various extents. The data further support and add to the reported cholinesterase activities determined electrometrically in wild birds in northern Iraq. The plasma and whole brain cholinesterases of the birds are highly susceptible to inhibition by organophosphate and carbamate insecticides as determined by the described electrometric method, and the results further suggest the usefulness of the method in biomonitoring wild bird cholinesterases.