Nonspecific Behavioral Effects Research Articles

Anosmia and aggression in male owl monkeys (Aotus trivirgatus)

Adult owl monkeys behaved aggressively when paired with unfamiliar members of the same sex. Males showed the greatest aggressive responses. When plugs containing bismuth iodoform paste were inserted into the nasal passages of male owl monkeys they fought less readily and showed less contact aggression. Although intermale aggression was not abolished anosmic males spent longer in proximity and showed an increase in olfactory inspections. Control experiments confirmed that the technique used to induce anosmia had blocked responsiveness to conspecific odours and that decreases in aggression were not due to discomfort or non-specific behavioral effects.

Behavioral and pharmacological specificity of the feeding elicited by cholinergic stimulation of the substantia nigra in the rat.

Microinjections of the cholinergic agonist carbachol into anterior substantia nigra dose dependently increased food intake in satiated rats. This resulted from a prolongation of the duration of eating. In the absence of food, those doses of carbachol that stimulated food intake (.1 and .5 microgram) had no effect on any other response examined, including gnawing, drinking, locomotion, grooming, sniffing, and rearing. The effect of carbachol depended on the degree of prior food deprivation, but supra-additive effects of carbachol and deprivation were not observed. These results are contrasted with those of previous studies demonstrating the nonspecific behavioral effects of electrical stimulation of the brain and of studies showing that carbachol has radically different behavioral effects at other central nervous system sites. Microinjection of an acetylcholine/eserine sulfate mixture also significantly increased food intake. This response was abolished by prior microinjection of the muscarinic receptor antagonist atropine into the substantia nigra, a result that provides evidence for pharmacological specificity of the behavioral effects. These data provide further evidence for the hypothesis that a functional cholinergic system is present within substantia nigra.

PHARMACO-ETHOLOGICAL ANALYSIS OF AGONISTIC BEHAVIOR BETWEEN RESIDENT AND INTRUDER MICE: EFFECT OF ANTICHOLINERGIC DRUGS

The resident-Intruder paradigm was employed in order to evoke an agonistic behavior in mice. In this situation a resident male mouse has been cohabiting with a female for 5 weeks, and an intruder male mouse is introduced into the resident’s home cage. A species-specific pattern of agonistic behavior was observed in all mice. The significance of cholinergic mechanisms in the mediation of the agonistic behavior was evaluated by pharmacological manipulations. Drugs were administered to resident mice. Scopolamine hydrobromide (0.25, 0.50 and 0.75 mg/kg, i.p.) significantly suppressed the resident’s aggressive episodes (offensive sideways posture, tail rattling and attack biting) in a dose-dependent manner, whereas the peripheral anticholinergic drug methylscopolamine nitrate (0.25, 0.50 and 0.75 mg/kg, i.p.) was ineffective. On the other hand, the resident’s locomotor activity and rearing response were significantly increased after the administration of scopolamine hydrobromide. The evidence suggests that brain cholinoceptive mechanisms may participate in the regulation of intraspecies aggressive behavior. However, it appears that other nonspecific behavioral effects of scopolamine cannot be ruled out.

Pharmaco-ethological analysis of agonistic behavior between resident and intruder mice: effect of anticholinergic drugs.

The resident-intruder paradigm was employed in order to evoke an agonistic behavior in mice. In this situation a resident male mouse has been cohabiting with a female for 5 weeks, and an intruder male mouse is introduced into the resident's home cage. A species-specific pattern of agonistic behavior was observed in all mice. The significance of cholinergic mechanisms in the mediation of the agonistic behavior was evaluated by pharmacological manipulations. Drugs were administered to resident mice. Scopolamine hydrobromide (0.25, 0.50 and 0.75 mg/kg, i.p.) significantly suppressed the resident's aggressive episodes (offensive sideways posture, tail rattling and attack biting) in a dose-dependent manner, whereas the peripheral anticholinergic drug methylscopolamine nitrate (0.25, 0.50 and 0.75 mg/kg, i.p.) was ineffective. On the other hand, the resident's locomotor activity and rearing response were significantly increased after the administration of scopolamine hydrobromide. The evidence suggests that brain cholinoceptive mechanisms may participate in the regulation of intraspecies aggressive behavior. However, it appears that other nonspecific behavioral effects of scopolamine cannot be ruled out.

Inhibition of cerebral protein synthesis: Dissociation of nonspecific effects and amnesic effects

Injection of 210 mg/kg of anisomycin 5 hr prior to training produced more nonspecific behavioral side effects at the time of training than did a low dosage (30 mg/kg) given 20 min prior to training. Yet the low dosage 20 min pretraining produced greater protein synthesis inhibition at training and greater impairment of retention of passive avoidance training than did the high dosage 5 hr pretraining. These results demonstrate that the level of protein synthesis inhibition at or near the time of training is the critical factor for inducing amnesia, and not nonspecific side effects of a protein synthesis-inhibiting drug. Various alternative hypotheses would also predict greater amnesia after the high dosage of anisomycin given 5 hr prior to training than after the amnestic low dose given 20 min prior to training. Thus, these results provide further support for the hypothesis that brain protein synthesis is required for long-term memory formation.

Nonspecific Behavioral Effects of Substances from Mammalian Brain

Nonspecific Behavioral Effects of Substances from Mammalian Brain

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