Effect of piracetam on one-way active avoidance in rats with medial thalamic lesions

Abstract

Rats sustaining either medial thalamic electrolytic lesions or sham operations were injected with either piractam (100 mg/kg), a drug previously shown to enhance acquisition, or saline for 3 consecutive days prior to being tested for shock-flinch threshold and one-way active avoidance. The animals with medial thalamic lesions were found to make fewer avoidances than the sham-operated animals. Piracetam was shown neither to alleviate the lesion-induced avoidance deficit nor to facilitate acquisition in the sham-operated animals. No differences were observed in shock-flinch threshold. 158Rats with relatively large lesions centered in the dorsomedial nucleus of the thalamus (DMT) have been found to be deficient on acquisition of one-way active avoidance (Tigner, 1972;Vanderwolf, 1964Vanderwolf, , 1966Vanderwolf, , 1967 Wuensch & Means, 1976). Several treatments, including septal lesions (Vanderwolf, 1964), warm-up period (Vanderwolf, 1966), electroconvulsive shock (Vanderwolf, 1968), and chlorpromazine injections (Wuensch & Means, 1976) have been found to partially alleviate the DMT lesion-induced active avoidance deficit. It has been suggested that all of the above treatments improve the performance of DMT-lesioned rats in avoidance conditioning by decreasing the tendency to behaviorally freeze when shocked. Further, it has been shown that amphetamine injections decrease the freezing behavior of DMT-lesioned rats in a two-choice discrimination task, but they do not improve choice performance (Wuensch, Broom, Means, & Harris, 1978). Thus, several treatments have been found to decrease the freezing behavior of DMT-Iesioned rats, but no treatment has been found that directly affects the acquisition process.Piracetam (2-pyrrolidone acetamide) has been proposed as a learning-facilitation drug (Giurgea, Note 1). In humans, it has been shown to alleviate some of the symptoms of senility (Stegnik, 1972). In rats, piracetam has been found to facilitate acquisition of a lightsignaled active avoidance in a Y maze (Wolthuis, 1971) and to reduce errors and escape latency in a four-choice water-filled maze (Giurgea & Mouravieff-Lesiusse, 1972). It has also been shown to protect against the amnestic effects of electroconvulsive shock (Sara & David-Remacle, 1974) and hypoxia (Giurgea, Lefevre, & Lescrenier, 1971;Sara & Lefevre, 1972 METHOD SubjectsA total of 41 individually housed , male, Long-Evans rats from the East Carolina University colony were used. All rats were given food and water ad lib.The study involved four groups. Eight rats received lesions centered on the DMT and were treated with piracetam (Group D-P). Group SoP (n =12) received sham operations and treatment with piracetam . Group D-S (n =9) received lesions centered on the DMT and saline. Group S-S (n =12) received sham operations and saline. ProcedureSurgery. Surgery was done under clean conditions ; sodium pentobarbital was used as anesthesia (Nembutal, 50 mg/kg) and .2 cc of BicilIin was administered to prevent infection. Subjects in Group D-P and Group D-...

BMY 21502 and piracetam facilitate performance of two-choice win-stay water-escape in normal rats

“…Piracetam has also protected rats from the amnesic effects of hypoxia (Giurega etal., 1971;Sara and Lefevre, 1972) and Hemicholinium-3 (Franklin et al, 1986), but not scopolamine (Petkov and Vug- , 1985), and diminished the effects of early sensory deprivation (Myslivecek and Hassmannova, 1973). However, it failed to enhance performance on shock avoidance tasks in mice (Vincent etal., 1984), younger and older rats , and medial thalamically-lesioned rats (Abbot and Means, 1979). Further, piracetam did not facilitate food-reinforced discrimination in either normal or thalamically-lesioned rats (Means etal., 1980 b).…”