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Tonic immobility in chickens was influenced by a variety of drugs that act on the adrenergic neurochemical system of the body. Alpha 1 agonists such as methoxamine and phenylephrine produced decreases in the duration of immobility, although the former compound also caused a significant increase in the immobility response at high dosages. Alpha 2 agonists(More)
Curiosity and general activity characteristics in different squirrel monkey (Saimiri sciureus) phenotypes were assessed. Ten infant squirrel monkeys, representing 2 subspecies (Bolivian and Colombian) and both genders, were observed on 4 testing sessions during which novel and familiar objects were presented to each subject. No consistent object-contact(More)
A series of five experiments examined the effects of two anticholinergic drugs, atropine and scopolamine, on the duration of tonic immobility (TI) and susceptibility to the TI response in both Production Red and White Leghorn chickens (Gallus gallus), in an attempt to resolve previous contradictory findings about the effects of cholinergic manipulations on(More)
Low doses of serotonin potentiated immobility durations in 2 1/2-week-old chickens (Gallus gallus) while high doses attenuated the response. Cyproheptadine, a serotonergic antagonist, eliminated increases generated by low doses of serotonin and reduced durations in control subjects, but had no effect on the attenuation produced by high doses of the drug.(More)
The effects of low and high doses of serotonin on tonic immobility (TI) duration and susceptibility in 10- and 45-day-old chickens were examined. High doses of serotonin reduced the number of inductions required to produce TI, regardless of the subject's age. In contrast, low and high doses of serotonin produced biphasic increases and decreases in TI(More)
Groups of young chickens were injected with various dosages of several alpha-adrenergic antagonists and tested for the effects of these drugs on tonic immobility. Yohimbine, a very potent alpha2 antagonist, produced a significant decrease in the duration of tonic immobility at doses of 1 mg/kg, while prazosin, a potent alpha1 antagonist, had no apparent(More)
In two experiments, groups of 2 1/2 to 3 week old chickens were injected intravenously with various dosages of serotonin and tested for tonic immobility. Relatively low doses of serotonin produced significant increases in the duration of immobility, while high doses only produced slight decreases in duration. Serotonin also reduced the activity levels of(More)