Plasma components of 6 to 12-month-old beagles were examined using a Technicon auto-analyzer. Age-related changes were noted for 8 of the 21 components: the levels of total protein (T. Pro) and iron (Fe) gradually increased while those of alkaline phosphatase (ALP), creatine phosphokinase (CPK) and inorganic phosphorus (Pi) persistently decreased in both sexes. Triglyceride (Trigly) in female dogs, glutamic-pyruvic transaminase (GPT) and urea nitrogen (Urea-N) in male dogs tended to increase. The following thirteen components showed no significant variation during the period of observation: glucose (Glu), lactic dehydrogenase (LDH), albumin (Alb), creatinine (Crea), glutamic-oxaloacetic transaminase (GOT), leucine aminopeptidase (LAP), total bilirubin (T. Bil), amylase (Amy), total cholesterol (T. Chol), sodium (Na), potassium (K), chloride (Cl) and calcium (Ca). Our results generally agree with the reported findings on beagles from various institutions.
The simultaneous recording system for body weight, food and water consumption and behavior (spontaneous motor activity and drinking and feeding behavior) of a mouse was developed. The body weight and food consumption were measured by force transducers. Food and water consumption and drinking and feeding behavior were measured by an infrared luminous diode and a phototransistor. Spontaneous motor activity was measured by photosensors. The system control and data acqusition were performed by using a personal computer. Every parameter could be monitored with a desired time interval. All the data collected by this system revealed apparent circadian rhythm. In conclusion, this system would be a powerful tool for pharmacological and/or toxicological research.
The novel enkephalin analog Tyr-D-Met(O)-Gly-EtPhe-NHNHCOCH3. AcOH (EK-399) was examined for psychic dependence potential by a self-administration test in rats. Five groups of experimentally naive rats were given an intravenous dose of EK-399 (0.032, 0.064 or 0.125 mg/kg), morphine HCl (0.5 mg/kg) or cocaine HCl (0.5 mg/kg) via a cannula implanted in the jugular vein when they pressed a lever. No animals initiated self-administration of EK-399 in the first 3 or 4 weeks of the experimental period. In contrast, almost all of the animals receiving morphine or cocaine initiated a high rate of self-administration within 1 or 2 weeks. However, when the doses of EK-399 were subsequently decreased, 4 of the 10 animals increased their rate of self-administration slightly. Furthermore, an increase in the rate of EK-399 self-administration was observed in l of 4 rats made physically dependent on EK-399. These results suggest that EK-399 has a very weak reinforcing effect on drug-taking behavior, which is slightly enhanced by the development of physical dependence on the compound, and it may possess a low psychic dependence potential.