Fouad K. Mohammad, Yaareb J. Mousa and Mohammad M. Hasan
الملخص العربي
The present study was undertaken to examine the acute toxicity (LD50) and neurobehavioral manifestations in
the open-field activity and tonic immobility tests in 7-14 day-old chicks treated with the H1-receptor antagonist
diphenhydramine. Plasma and whole brain cholinesterase activities were also determined in the chicks. The LD50 of
diphenhydramine in chicks was 49.3 mg/kg, intramuscularly (i.m.). The signs of diphenhydramine toxicosis in the
chicks which appeared within one hour after injection included excitation, jumping, whole body tremor, ataxia,
gasping, frequent defecation, paralysis and recumbency. Fifteen minutes after i.m. injection, diphenhydramine at 2.5
and 5 mg/kg decreased the general locomotor activity of the chicks in the 5-min open-field activity test, as seen by a
significant increase in the latency to move from the center of the open-field arena and decreases in the numbers of
lines crossed and escape jumps in comparison with control values. Diphenhydramine significantly decreased the frequencies
of pecking and defecation only at 5 mg/kg when compared with respective control values. Diphenhydramine
treatments at 2.5 and 5mg/kg also significantly increased the durations of tonic immobility of the chicks and
decreased their whole brain cholinesterase activity by 33 and 30%, respectively, in comparison with the control
values. In conclusion, the data suggest that diphenhydramine induces central nervous system depression in chicks at
doses below the LD50 value of the drug which is reported here for the first time.
يعرب جعفر موسى | Yaareb Jaafar Mousa | 5713