Forskolin suppresses seizures induced by pentylenetetrazol in mice

Forskolin, an adenylate cyclase activator when injected s.c. (1 mg/kg) in mice, caused an elevation of cAMP in the forebrain and cerebellum of up to 170% and 130%, respectively. The treatment was found to prevent seizures induced by pentylenetetrazol. This suppression had subsided 30 min after the injection, when cAMP level was again normal in the cerebellum but still elevated in the forebrain.     

Influence of diet on plasma tryptophan and brain serotonin levels in mice

Summary Groups of mice were maintained for up to 78 weeks on tryptophan restricted, protein restricted and control diets. Plasma tryptophan levels were significantly reduced by both forms of dietary restriction. Brain serotonin levels were significantly reduced only in mice on the tryptophan restricted diet, but not for mice on the protein restricted diet. The protein-restricted diet contains less of the large neutral amino acids which compete with tryptophan to enter the brain. It is known that protein restriction and tryptophan restriction extend lifespan. The results presented here suggest that extension of lifespan and lowering of brain serotonin are not related.     

Ultrastructural changes in uterine myometrium of mice with experimentally-induced adenomyosis

Summary Ectopic pituitary transplantation induced a high incidence of adenomyosis in SHN mice. Early signs of the development of adenomyosis were the penetration of stromal connective tissue into myometrium followed by uterine gland invasion. Associated with these changes, the inner layer of myometrium showed the involution of smooth muscle cells and distended intercellular spacesThis work was supported in part by Grant-in-Aid for Scientific Research from the Ministry of Education, Science and Culture of Japan     

Immune-mediated glomerulonephritis induced by mercuric chloride in mice

Summary The BALB/c mouse developed mesangial deposits of immune constituents and light microscopical changes characteristic of immune complex glomerulonephritis after 8 weeks' treatment with mercuric chloride given by s.c. injection. There were no signs of linear of granular immune deposits along the glomerular capillary basement membrane after 2 or 8 weeks. The antigen could not be identified. No antibodies to nuclear or renal structures were found. Using a histochemical method (silver amplification) mercury was detected by light and electron microscopy in tubular and glomerular structures. Mercury was present in secondary lysosomes of the mesangial cells after eight weeks of mercury poisoning.We are deeply indebted to Dr. Gorm Danscher, Institute of Anatomy, B., University of Aarhus, Denmark, for valuable discussions and technical advice. This work was supported by the Swedish Medical Research Council, project no 6536.     

Suppression of the immune response by drugs interfering with the metabolism of serotonin

Summary The work was based on the assumption that neurohumoral control of the immune response, particularly in stressed animals, involves central serotoninergic mechanisms. Rats immunized with sheep erythrocytes were stressed by repeated restraints and/or treated with a precursor of serotonin (5-hydroxytryptophan, 5-HTP) or with an inhibitor of serotonin synthesis (parachlorophenylalanine, PCPA). As expected, repeated stresses reduced the plaque-forming cell (PFC) response. Treatment with 5-HTP also reduced the PFC response, and potentiated the immunosuppressive effect of stress. This was accompanied by increased metabolism of serotonin in the brain, as indicated by increased concentration of its metabolite, 5-hydroxyindoleacetic acid (5-HIAA), in cerebral tissue. Treatment with PCPA also suppressed the PFC response, but this suppression was accompanied by decreased levels of brain serotonin and of 5-HIAA. Plasma corticosterone levels were elevated in rats treated with PCPA. It seems that putative central effects of PCPA on serotoninergic regulation of the immune response were outweighed by its effects on corticosterone secretion and/or on lymphoid cells.     

Circling behavior induced by phencyclidine in mice and its inhibition by naloxone

Summary Phencyclidine (PCP), when given to mice, induces general hyperactivity and rapid circling, similar to that caused by morphine. These effects are partially antagonized by naloxone.Acknowledgment. We are grateful to Professor A. Kalir for the donation of PCP. Correspondence and reprint requests should be addressed to A. M. Korczyn.     

Alopecia induced in young mice by exposure to excess dietary zinc

Summary Second generation mice were exposed to normal (50 ppm, Group I) or excess (2000 ppm, Group II) zinc in the maternal diet during gestation and lactation, then weaned and continued on the mother's diet until sacrifice at 8 weeks. Tibia zinc reflected dietary intake. Group II had reduced plasma copper, body weight, and hematocrit; the second coat of hair appeared late and was lighter in color than Group I, possibly as an effect of copper and pigmentation development and hair growth.