Effects of apomorphine and haloperidol on response suppression learning of young chicks.

Abstract

In four experiments, the effects of augmenting or blocking dopamine receptor activity on response suppression learning of Colburn X Colburn chicks were determined. In each experiment, 4-day-old chicks were trained to key peck for heat reward and then tested for response suppression learning by using either a response-contingent punishment or an extinction-punishment task. Before response suppression testing, different groups of chicks were injected ip with apomorphine (1.0, 2.0, or 4.0 mg/kg) either alone or after pretreatment with haloperidol (0.5 or 1.0 mg/kg). Regardless of the response suppression task used, chicks injected with apomorphine had difficulty inhibiting their responding; whereas, chicks injected with haloperidol, either alone or before apomorphine treatment, responded on fewer trials than saline-treated chicks. During extinction testing, 4-day-old chicks given only apomorphine showed the typical suppressive effect of punishment on responding rather than the paradoxical punishment-induced increase in responding found in normal 1-day-old chicks. These results indicate that activation of dopamine receptors retards response suppression learning of the 4-day-old chick, but functional changes in central dopaminergic mechanisms are not primarily responsible for the normal age-dependent improvement in response suppression learning of the young chick.

Dopamine antagonists produce an age‐dependent increase in the responding of the young chick

“…Normally, after brief reward training, 4-day-old chicks inhibit their punished key-peck responses more quickly than do l-day-old chicks (see Mattingly & Zolman, 1980). This same age-dependent difference in punished responding was observed across this series of experiments as l-day-old saline controls responded on 51% and 47% of the punishment trials in Experiments 1 and 2, and 4-day-old saline controls responded on only 33% and 25% of the punishment trials in Experiment 2 and in the third experiment of McDougall et al (1987). Therefore, in Figure 3 the punished key-peck responding of 1-and 4-day-old chicks pretreated with different doses of haloperidol is expressed relative to the key-peck performance of their age-matched saline controls (mean punished response trials for drug-dose groupdmean punished response trials for age-matched saline controls x 100).…”

“…Furthermore, in Experiment 2 haloperidol depressed significantly the key-peck responding of the 4-day-old chick during acquisition training, but this depressive effect on acquisition was not significant in other punishment experiments with 4-day-old chicks (see McDougall et al, 1987). Because of the rapid acquisition of key-peck responding by both 1 -and 4-day-old chicks the response-contingent punishment paradigm with only 12 nonshock acquisition trials would not be a very sensitive test for determining whether dopamine antagonists produced differential age effects during appetitive training.…”

Dopamine D‐2 receptor mediation of response suppression learning of young rats

“…Likewise, apomorphine disrupts the 4-day-old chick's ability to inhibit key-pecking that results in both reinforcement and wing-shock. Haloperidol (a nonspecific DA receptor antagonist) completely attenuates this apomorphine-induced pecking, and 4-day-old chicks given haloperidol alone inhibit their punished responding even more quickly than saline-treated controls (McDougall, Zolman, & Mattingly, 1987). In contrast, haloperidol has the opposite effect in 1-day-old chicks, as haloperidol-treated 1-day-olds respond on significantly more responsecontingent punishment trials than their saline-treated age-mates (Zolman & McDougall, 1986).…”

“…In the initial experiment, age-dependent changes in the response suppression learning of preweanling rat pups were assessed using a massed-trial punished appetitive approach task. In the young chick, a similar key-peck procedure has been used successfully to measure response suppression learning, and is quite sensitive to both age differences and drug manipulations (Mattingly & Zolman, 1980;McDougall et al, 1987).…”

Localization of dopamine D1 receptors and dopaminoceptive neurons in the chick forebrain

“…Biochemical investigations revealed changes of DA-stimulated cAMP-synthesis in relation to auditory imprinting (Reiser et al, 1995). The dopaminergic system is involved in a broad array of behavioral responses and in learning paradigms in birds such as stereotyped pecking (Cheng and Long, 1974;Brunelli et al, 1975;Zarrindast and Amin, 1992), yawning and sedation (Ferrari and Giuliani, 1993), passive avoidance training (Stewart et al, 1996), and response suppression learning (McDougall et al, 1987;Zolman and McDougall, 1990). Although there is increasing knowledge about the organization of the dopaminergic innervation of the avian forebrain Waldmann and Gü ntü rkü n, 1993;Moons et al, 1994;Reiner et al, 1994;Wynne and Gü ntü rkü n, 1995;Karle et al, 1996;Metzger et al, 1996), only little is known about the distribution (Richfield et al, 1987;Dietl and Palacios, 1988;Casto and Ball, 1994) and role (Schnabel and Braun, 1996;Stewart et al, 1996) of the different DA receptor families and the associated intracellular messenger systems.…”