Catecholaminergic drug and conditioned emotional response in the white rat

Abstract

This experiment was conducted to examine the effect of change of catecholamine (CA) by catecholaminergic drug on animal emotional behavior. 32 male wister strain albino rats were randomly allocated to one of four groups. As summerized in Table 1, α-methyl-p-tyrosine (α-MT, 75 mg/kg, i. p.), namely CA synthesis inhibitor was administered 4.5hr. before test for Group A and Group AD. For Group D and Group AD, L-DOPA (50 or 100 mg/kg, i. p.), namely the precursor of CA was administered 1.5 hr. before test. For Group S, saline was administered. Animals were tested by conditioned emotional response (CER) in operant conditioning in Skinner box.L-DOPA significantly increased conditioned suppression in CER. α-MT alone did not affect conditioned suppression in CER, but pretreatment of α-MT significantly suppressed the increase of conditioned suppression by L-DOPA (Fig. 2, Fig. 3). According to the above results, it is supposed that increase of CA by L-DOPA enhanced emotionality and CER in Skinner box, whereas α-MT suppressed the enhancement of emotionality by L-DOPA. It was suggested that CER test measure is sensitive to slight increase of CA by low dose of L-DOPA.