Biomedical subjects

G J Schaefer

Publications and source records attributed to G J Schaefer.

39 records · Page 3Linked to original sources

PubMedDate not supplied

p-chloroamphetamine: behavioral effects of reduced cerebral serotonin in rats.

p-Chloroamphetamine (PCA), a serotonin depletor, was given to rats at least 24 h prior to testing in an open field or a shock avoidance Y-maze task. In the open field PCA groups showed hypoactivity and increased defecation up to 30 days after drug administration. These same animals plus independent groups of PCA animals, showed facilitated avoidance acquisition in the Y-maze up to 15 days after PCA administration. At the beginning of behavioral testing serotonin levels in PCA animals were reduced 70 percent and were still reduced 41 percent after 38 days in whole brain. These results suggest a separation between shock and non-shock effects of brain serotonin depletion. The facilitated avoidance also provides support for the role of serotonin as an inhibitory neurotransmitter mediating a behavioral suppression system.

Amphetamines↗

PubMedDate not supplied

Ethanol and current thresholds for brain self-stimulation in the lateral hypothalamus of the rat.

Two groups of animals were implanted with stimulating electrodes in the lateral hypothalamus for intracranial self-stimulation (ICSS). Following surgery these animals were trained in the auto-titration, brain self-stimulation procedure which measured both the rate of responding and the reinforcement threshold for electrical stimulation. When behavior was stable, one group was given saline or ethanol (0.1-1.7 g/kg) administered intraperitoneally (IP) either 15 or 60 min before testing. The other group was given saline or ethanol (1.0-4.5 g/kg) administered intragastrically (IG) 15 or 60 min before testing. With IP administration, there was a graded decrease in lever-pressing at 15 min but the effect was less obvious at 60 min. There were no changes in threshold except at the highest dose when behavior was disrupted. With IG administration, a reduction in the rate of responding occurred at 15 min only. No changes in thresholds were observed at any dose level or injection-test interval. Thus, administration of ethanol either by the IP or IG route did not affect the reinforcement thresholds for ICSS in the lateral hypothalamus, and these results contrasted with those of other drugs of abuse such as amphetamine or morphine.

Animals↗

PubMedDate not supplied

Effects of an alcohol diet on locomotor activity and the acquisition of brain self-stimulation in rats.

Male rats (n = 45), implanted with stimulating electrodes in the lateral hypothalamus for intracranial self-stimulation (ICSS), were allocated to three groups equalized for body weights. One group was given an alcohol liquid diet (Lieber-DeCarli) diet as the sole source of food; a second group was given a control liquid diet in which carbohydrates were substituted for alcohol; and a third group was maintained on standard laboratory chow and water. After four weeks on these diets, all animals were tested during the fifth week of the diets for locomotor activity in five daily 15-min sessions, and their reactivity to handling was also measured. During the sixth and seventh weeks of the diets, animals were allowed to self-train for ICSS during daily 15-min sessions. In the eighth week blood alcohol levels were measured. There were no differences between groups in locomotor activity or reactivity to handling. However, when tested for the acquisition of ICSS, animals on the diet containing alcohol made fewer responses than did those receiving the two control diets (p less than 0.001). The mean blood level of alcohol in the alcohol-consuming group at the time of day of behavioral testing was 50.6 +/- 5.0 mg/dl. These results suggested that the chronic ingestion of an alcohol-containing diet which resulted in only moderate blood levels of alcohol may not affect simple behavior such as locomotor activity, but may produce decrements in the performance of a more complex task such as lever pressing for ICSS.

Analysis of Variance↗