Until recently, a capacity for apoptosis and synthesis of nitric oxide *NO) were viewed as exclusive to multicellular organisms. The existence of these processes in unicellular parasites was recently described, with their biological significance remaining to be elucidated. We have evaluated L-arginine metabolism in Trypanosoma cruzi in the context of human serum-induced apoptotic death. Apoptos...

The aim of the present study was to explore the effect of nitric oxide on leptin immunoexpression and innervation in interscapular brown adipose tissue (IBAT) of room- and cold- acclimated rats. Animals acclimated both to room-temperature (22 +/- 1 degrees C) and cold (4 +/- 1 degrees C) were treated with L-arginine, a substrate for nitric oxide synthases (NOSs), or N?-nitro-L-arginine methyl e...

N-methyl D-aspartate (NMDA) receptor stimulation is known to activate nitric oxide (NO) synthase, an enzyme present in a high proportion of sympathetic preganglionic neurons. In this study, we have examined the possibility that NO modulates the pressor responses elicited by NMDA receptor stimulation in the spinal cord. In experiments on anesthetized rats, we determined whether intrathecal admin...

Polyaspartoyl.l-arginine (PDR) is an inhibitor of platelet aggregation ex vivo but in vitro. This study attempts to elucidate the target cell of PDR action and its action mechanism. PDR (1.7-170 microg/ml) significantly inhibited platelet aggregation in vitro in the presence of rat aortic endothelial cells (RAEC), NO synthase inhibitor N-nitro-l-arginine methyl ester (l-NAME) inhibited this eff...

The germination of Bacillus cereus T spore suspensions is partially prevented by several inhibitors of trypsin-like enzymes. Leupeptin, antipain, and tosyl-lysine-chloromethyl ketone are effective inhibitors, whereas chymostatin, elastatinal, and pepstatin are inactive. A synthetic substrate of trypsin, tosyl-arginine-methyl ester, also inhibits germination. Its inhibitory effect decreases as a...

Methylglyoxal (MG), a reactive metabolite of glucose, has high affinity for arginine and is a precursor of advanced glycation endproducts (AGEs). We tested the hypothesis that L-arginine, and its inactive isomer D-arginine, can efficiently scavenge MG, administered exogenously or produced endogenously from high glucose, and attenuate its harmful effects including endothelial dysfunction and oxi...

We have reported recently that the renal angiotensin II type 2 (AT2) receptors are upregulated and involved in promoting natriuresis/diuresis in obese but not in lean Zucker rats. In the present study, we tested the hypothesis that there is an enhanced AT2 receptor signaling via NO/cGMP pathway leading to greater inhibition of the Na(+), K(+)-ATPase (NKA) activity in the proximal tubules (PT) o...

Introduction: N- nitro-L-arginine methyl ester (L-NAME), one of the L-arginine analogs, has been specified as an inhibitor of nitric oxide synthase ( NOS).Nitric oxide synthase is an enzyme which leads to nitric oxide synthesis. Since nitric oxide has been known as a pain mediator, it can be said that L-NAME can decrease and relieve pain. In this research the effect of L-NAME on morphine antino...

Nitric oxide (NO), which occurs as a gaseous chemical messenger in the brain, is synthesized from L-arginine by nitric oxide synthase (NOS) as a coproduct of L-citrulline (1). NO has been well documented to have a neurotransmitter/neuromodulator role in the brain (2). Studies carried out on passive avoidance response of rats treated with Larginine and N-nitro-L-arginine methyl ester (L-NAME), a...