Screening of antiserotoninergic drugs with the genetically dystrophic chicken.

Line 413 early-onset, genetically homozygous dystrophic chickens were given twice-daily intraperitoneal injections of the antiserotoninergic drugs p-chlorophenylalanine hydrochloride, fluoxetine hydrochloride, ergonovine maleate, nortriptyline hydrochloride, methiothepin maleate, and methysergide bimaleate in combination with penicillamine. Except in one case, treatment with drugs significantly prolonged the righting ability of the treated dystrophic chickens, as measured by a periodic standardized flip-test procedure. Abnormally high levels of plasma creatine phosphokinase, lactate dehydrogenase, and SGOT were found in the untreated dystrophic chickens. However, of the drug-treated dystrophic chickens, in some cases the plasma enzyme activities were reduced whereas in others they were enhanced. In agreement with previous findings, the blood serotonin levels of the dystrophic chickens were found at all age groups to be significantly higher than those in the corresponding normal chickens. This phenomenon may in part account for the improvement in righting ability demonstrated in the dystrophic chickens receiving treatment with antiserotoninergic drugs.