p-Chloroamphetamine: Effects on tonic immobility, activity, and temperature in chickens.

Abstract

The effects of p-chloramphetamine (PCA) on tonic immobility (TI) duration, activity and temperature in chickens were examined in 6 experiments. In experiment (exp) 1, i.p. doses of 10 or 15 mg/kg PCA produced a significant attenuation of TI duration. The involvement of norepinephrine or dopamine in this effect is questionable since catecholamine synthesis inhibition with .alpha.-methyl-p-tyrosine in exp 2 did not alter the PCA attenuation of TI duration. In the 3rd and 4th exp, serotonin synthesis inhibition with p-chlorophenylalanine produced a blockade of the PCA effect on TI when subjects were tested at 60, but not 10, min after PCA injection. A competing response interpretation of the PCA effect in terms of enhanced motor activity was ruled out in exp 5 since, in contrast to the hyperactivity observed in mammals, PCA produced a decrease in both open-field and stabilimeter activity. A PCA-induced decrease in core temperature was observed in exp 6 and this effect also contrasts with the hyperthermia reported in rats following PCA injection. These results provide additional evidence that drug treatments that produce a serotonergic behavioral syndrome in rats result in attenuated TI duration in chickens, and they further document the existence of a curious mammalian-avian reversal in drug effects.