Brent C. White

Caffeine pretreatment: Enhancement and attenuation of d-amphetamine-induced activity

Caffeine pretreatment was studied for its effects on d-amphetamine-induced locomotor activity. Caffeine (30 mg/kg) was given either simultaneously with or at one of several intervals (0.5, 1.5, 4.5, 12, and 13.5 hours) before d-amphetamine (1.5 mg/kg). Enhancement of d-amphetamine activity occurred with simultaneous and 30 min caffeine pretreatment. However, when given 12 or 13.5 hours before d-amphetamine, caffeine diminished the activity, measured in stabilimeter cages. Several doses of caffeine (7.5, 15, 30, and 60 mg/kg) were given in multiple treatments ending 12 hours before d-amphetamine (1.5 mg/kg) to determine the effective doses for attenuation of d-amphetamine-induced activity. Only 30 and 60 mg caffeine doses reduced d-amphetamine activity while also interfering with body weight gain.

Specific gravity and creatinine as corrections for variation in urine concentration in humans, gorillas, and woolly monkeys

Hormones excreted in the urine are widely used to assess the physiological and psychological condition of unrestrained animals. In order to control for variation in the water concentration of urine samples, the hormone concentration is often indexed to the concentration of creatinine. Because there are several problems with using creatinine, we have investigated the efficacy of specific gravity as an alternative basis for adjusting the hormone concentration in humans, gorillas, and woolly monkeys. In an experimental manipulation of human urine hydration, ten volunteers drank a water load proportional to body weight, and provided complete urine collection and saliva samples for four consecutive 20 min intervals. From the urine, we measured cortisol (radioimmunoassay), creatinine (colorimetric assay), and specific gravity (refractometer). Only cortisol was assayed from saliva. During 80 min following water ingestion, cortisol, creatinine, and specific gravity declined as urine became diluted; however, total cortisol excretion remained constant. Only cortisol concentration indexed to specific gravity accurately reflected the consistent cortisol excretion. Specific gravity and creatinine‐corrected cortisol values were highly correlated but were significantly different. Salivary cortisol provided evidence for the relative stability of serum cortisol. To determine the utility of these corrections in other primates, we compared specific gravity‐ and creatinine‐corrected cortisol in urine samples from captive gorillas (N=16) and woolly monkeys (N=8). As with the human study, the two corrections were strongly correlated in each species, but the means were different. Specific gravity correction was superior in revealing the circadian variation in cortisol. Am. J. Primatol. 72:1082–1091, 2010.

Bird predation by captive woolly monkeys (Lagothrix lagotricha)

Vertebrate predation has not been reported for woolly monkeys (Lagothrix lagotricha) in their natural habitat. However, bird predation has been observed in captivity. The present report is based on 15 incidents of bird predation that occurred during a 1-year observational study of the nine woolly monkeys at the Louisville Zoo. All identified captures were by females. The captor and her prey were frequently pursued by the other monkeys. Social rank was related to attempts to steal the prey. Consumption was characterized by much chewing and frequent alternation between the prey and highly fiberous substances. Predation was not characterized by stereotypical behaviors for pursuit or killing of prey, but instead suggested opportunistic capture by a generalized organism. The low frequency of bird predation by captive woolly monkeys may indicate that a similar level of predation has gone undetected in the study ofLagothrix in the wild.

Unilateral catecholamine depletion of the corpus striatum and amphetamine-induced turning: An ontogenetic study

Unilateral intrastriatal microinjections of α-methyl-p-tyrosine followed by systemic amphetamine treatment produced turning ipsilateral to the side of the injection in rats from 12 days of age to maturity, but not in rats younger than 12 days. These results are consistent with other findings that indicate rapid development of the striatal dopaminergic system and dopaminergic component of the amphetamine stereotypy in the second postanatal week.

Chest-rubbing in Captive Woolly Monkeys (Lagothrix lagotricha)

The correlates of chest-rubbing were studied in a captive group of woolly monkeys (Lagothrix lagotricha) to assess possible functions of territorial marking, spacing among competing groups or competing males, reproductive communication, marking to identify familiar environments, selfanointing, and displacement activity. Chest-rubbing was observed only in sexually mature monkeys and was a predominantly male activity. Females increased chest-rubbing when the original adult male died. Chest-rubbing by the first adult male was more common during the two months that he was mating with two females and at times when keepers were likely to be at the exhibit. The results suggest a reproductive function for chest-rubbing in both males and females. There is also support for chest-rubbing as a spacing activity.

Caffeine-induced taste aversion and mimetic responses

Novel tastes preceded a range of caffeine doses (10-80 mg/kg) in a taste aversion training trial. One week later rats which had doses of 30 mg or higher showed strong aversions as measured by a single bottle consumption test. The 10 and 20 mg dose produced the most hyperactivity and apparently enhanced intake of the taste paired with caffeine. During the training trial, rats receiving the 80 mg dose exhibited copious gapes and chin-rubs, mimetic responses to noxious tastes. Gapes also occurred in these subjects during the aversion test. Consumption was more sensitive than mimetic responding as a measure of the aversive effects of caffeine. Only the 80 mg dose produced neophobia. Tests with isotonic injections indicated that tonicity was not the source of the aversions.

Caffeine reduces amphetamine-induced activity in asymmetrical interaction

Caffeine-amphetamine interactions were studied to determine whether attenuation of amphetamine-induced activity by caffeine pretreatment (30 mg/kg) is the result of increased or decreased sensitivity to amphetamine. Caffeine pretreatment attenuated amphetamine activity in the rats without producing a horizontal shift in the dose-response curve. Results support a reduction in sensitivity to amphetamine. A cross-tolerance design revealed an asymmetrical interaction between caffeine and amphetamine. Multiple caffeine treatments (30 mg/kg) produced tolerance and attenuation of subsequent amphetamine activity (1.5 mg/kg). Amphetamine did not produce tolerance or affect subsequent caffeine-induced activity.

Behavior and Husbandry of a Captive Group of Woolly Monkeys: A Case Study

With the addition of six woolly monkeys to its colony in the mid-1980s, the Louisville Zoo began a decade of successful breeding with 21 live births. We also initiated a systematic study of behavioral and environmental correlates of urinary cortisol excretion with the goal of understanding factors that contribute to hypertension in captive woolly monkeys. Urinary cortisol had a curvilinear relationship with social standing as measured by scream incidents. Cortisol was higher in females than males. Cortisol increased as females approached the normal term of their pregnancies. Three breeding females showed an association between cortisol and visitors, which may be confounded by ambient temperature. Otherwise, season, age, and housing condition (bachelor, breeding, mixed nonbreeding) did not affect cortisol excretion. Several varieties of social greetings were observed during calm interactions as well as after conflicts. Proximity among individuals reflected matrilineal grouping for mother-raised monkeys. Species-typical behaviors such as chest rubbing, predation, and social greetings were consistent with these behaviors as described in wild populations.