Charles N. Stewart

Animal-Assisted Activity: Effects of a Complementary Intervention Program on Psychological and Physiological Variables.

Animal-assisted activity is the use of trained animals for the therapeutic, motivational, or educational benefit of patients. Subjects of this study were 218 patients hospitalized on the mental health unit of a community hospital with an existing, complementary animal-assisted activity program. Half of the patients participated in a 1-hour session of animal-assisted activity. The other half, who served as a comparison group, participated in a 1-hour stress management program. It was hypothesized that an animal-assisted activity program would improve ratings of depression, anxiety, and pain and the associated physiological measures of stress and discomfort. Self-report ratings of depression, anxiety, and pain were collected before and after treatment sessions, and blood pressure, pulse, and salivary cortisol were measured. There were significant decreases in depression (P < .0001), anxiety (P < .0001), pain (P < .0001), and pulse (P < .04) after animal-assisted activity program, comparable to those in the more traditional stress management group.

Elevated shock threshold in sexually receptive female rats

Previous studies have found cyclic differences in wheel running, extinction of conditioned avoidance responses, and open field behavior as a function of the estrous cycle in rodents. The purpose of this study was to investigate possible sensory changes associated with estrus in rodents. Female rats were monitored for behavioral and physiological changes related to the estrous cycle. Using the method of constant stimuli and foot shock, jump thresholds were determined during the estrous cycle stages of sexual receptivity (proestrus) and non-receptivity (metestrus). A significantly higher jump threshold was demonstrated by animals during proestrus as compared to metestrus. Possible explanations for the failure of previous investigators to find attenuated sensitivity as a function of the estrous cycle are discussed.

Electroencephalographic study of l-glutamate induced seizures in rats☆

Abstract The ip administration of l -glutamate was found to induce clonic movements and tonic-clonic seizures in rats at a dose level of 2.0 mmole/100 g body weight. The susceptibility to the seizures was not affected by dietary pyridoxine deficiency. The seizure episodes were characterized by 3–5 cps high amplitude spikes ranging from 200 μV/cm to 1000 μV/cm. In the interseizure periods records showed 1 cps high voltage slow waves. The results are discussed in terms of possible biochemical mechanisms operative in the glutamate induced seizures.

Shuttle box avoidance learning and epinephrine

Rats were trained on a two way shuttle avoidance response under one of two doses of epinephrine or placebo conditions. No effect of the hormone was found in female rats, while males learned less effectively under high doses of the hormone. No facilitation of avoidance learning was found at either dosage.

Effect of epinephrine on acquisition of conditioned fear

Abstract In two separate experiments it was shown that injected epinephrine had no effect on the acquisition of conditioned fear. In both experiments, fear conditioning (and epinephrine injections) were separated in time from behavioral tests designed to measure fear acquisition, thus precluding confounding of results by possible side effects of the hormone on performance. Experiment 1 showed, specifically, that epinephrine did not affect suppression of an appetitive response by a CS associated with shock; Experiment 2 indicated that epinephrine did not affect escape reaction to a CS associated with shock.

The effect of epinephrine on extinction of an avoidance response

The effect of three dose levels of epinephrine upon extinction of an avoidance response was studied. It was hypothesized that a low dosage would prolong extinction because of increased sympathetic arousal and that this effect would be masked in the high dose group because of motor impairment. No significant effect of the hormone on trials to reach the extinction criterion was found but the high dose group showed significantly greater running times on the first five extinction trials.

Regional distribution of pyridoxal-5′-phosphate in developing and mature brains and its depletion in pyridoxine deficiency

A study was made of (a) the distribution of the coenzyme pyridoxal-5′-phosphate (PLP) in four discrete regions of developing and mature rat brains and (b) the effect of dietary pyridoxine deficiency on the distribution. There was an increase in PLP concentration of all the regions from infancy to adulthood. Highest concentration of PLP was found in the medulla and pons in both infants and adults. Pyridoxine deficiency resulted in a more marked reduction of PLP in all regions of the neonatal brain as compared with those in the mature brain. This is consistent with the vulnerability of the developing brain to nutritional stresses.

Failure to transfer a learned response in rats using a brain extract containing RNA

An attempt was made to transfer a learned response between individual rats by means of brain extracts containing RNA. Donors were trained on a light-dark discrimination task with a food reward in a “Y” maze. Control groups consisted of donors given non-discriminative experience in the maze equal to that of the trained group, donors maintained in their home cages, and a saline control group. Recipient Ss did not differ significantly either in the number of errors made during training, or in the number of trials necessary to meet a criterion of five consecutive correct responses.

The role of blood glucose in activity related self-starvation

Rats in the experimental group lived in activity wheels on a 23-h deprivation schedule, while those in the control group lived in laboratory cages on the same feeding schedule. Blood-glucose determinations made on the 1st, 3rd, and 6th days of deprivation indicated that, while both groups were hypoglycemic on Days 1 and 2, by Day 6 the experimental Ss were still hypoglycemic, while control Ss’ blood-glucose levels approached normal ad lib levels. The results are in opposition to the hypothesis of glucocorticoid involvement in activity-related self-starvation.

Hypoglycemia in biotin deficiency

Abstract Impairments in glucose metabolism 1,2 and central nervous system function 3−7 as a consequence of biotin deficiency in rats hase been demonstrated earlier. A marked fasting hypoglycemia has been observed in the deficient rat which has been found to respond readily to biotin treatment. These data are presented in this paper.