Cobalt-mesoporphyrin inhibits heme oxygenase activity but it does not induce lipid peroxidation in rat brain membranes during photoirradiation.

We examined the effects of cobalt-mesoporphyrin (CoMP) in vitro. The porphyrin inhibited the activity of rat splenic heme oxygenase but scarcely stimulated peroxidation of lipids in a membrane fraction from rat brain during photoirradiation. The apparent inhibition constant for CoMP was 344 nM.

Protection by L-ascorbic acid against phototoxicity in tin-protoporphyrin-treated suckling rats.

The protective effect of free radical scavengers against phototoxicity was investigated with tin-protoporphyrin (SnPP)-treated suckling rats. Six kinds of scavengers (L-ascorbic acid, reduced glutathione, alpha-tocopherol, retinol, uric acid and cystine) were intraperitoneally injected to rats treated with SnPP plus photoirradiation. Among them, L-ascorbic acid was found to be most effective in protecting SnPP-treated rats against phototoxicity.

An acceleration of age-related increases in levels of the beta-subunit of nerve growth factor in selected tissues from senescence-accelerated mice (SAM-P/8).

An investigation was made of age-related changes in levels of the beta-subunit of nerve growth factor (beta-NGF) in selected tissues and of testosterone in serum in senescence-accelerated mice (SAM-P/8) and in the control mice (senesence-resistant mice; SAM-R/1). The concentrations of testosterone in serum were higher in SAM-P/8 than in SAM-R/1 at ages 2 and 4 mo. The level of beta-NGF in the thymus from SAM-R/1 increased with age, resulting in a statistically significant difference in its level between mice at ages 2 and 12 mo.

Nerve growth factor-induced changes in the structure of sulfated proteoglycans in PC12 pheochromocytoma cells.

Structural changes in proteoglycans (PGs) were examined during the neuritogenesis of PC12 cells induced by nerve growth factor (NGF). (1) A heparan sulfate (HS) PG and a chondroitin sulfate (CS) PG were synthesized by PC12 cells, irrespective of the presence of NGF or the duration of culture. PGs released from PC12 cells into the culture medium were mostly CSPGs.

Evidence for the presence of L-arginine in the glial components of the peripheral nervous system.

L-Arginine is a precursor of nitric oxide that has been identified as an endogenous activator of soluble guanylate cyclase. We have recently reported the immunocytochemical localization of free L-arginine in glial cells in the central nervous system (CNS) using specific anti-arginine antibody. In the present study, we focused our attention on this particular amino acid in the peripheral nervous system (PNS).