Controversy about proconvulsant and anticonvulsant nitric oxide (NO) effects and the place of oxidative stress in convulsions, are still a matter of research. We investigated the interaction between 2-amino-5-phosphonovaleric acid (APV), a competitive N-methyl-D-aspartate (NMDA) receptor antagonist and Nw-nitro-L-arginine methyl ester (L-NAME), a nonselective nitric oxide synthase (NOS) antagonist, in pentylenetetrazole (PTZ)-induced convulsions. Pentylenetetrazole was applied to adult Wistar rats intraperitoneally (ip) in a single dose of 80 mg/kg, and L-NAME (10 µg/10 µl) or APV (20 µg/10 µl) intracerebroventricularly (icv), 30 and 10 minutes before PTZ, respectively. In the same manner, another group received both antagonists. Control animals were given 0.9% saline. Nw-nitro-L-arginine methyl ester exerted a weak anticonvulsant effect, preventing generalized clonic (GCC) and clonic-tonic convulsions (CTC) in 17% of cases. With APV protection against GCC and CTC was 100%, forelimb dystonia (FLD) was decreased in 33% of cases, and time to onset of all convulsive patterns was prolonged (p<0.05 to 0.01). All effects of APV, except in CTC, were reversed by L-NAME applied prior to APV. In APV-PTZ treated animals, superoxide anion content was increased in the forebrain cortex, striatum and hippocampus, without an overwhelmed antioxidative superoxide dismutase (SOD) defense system in the other treatments. When the APV-PTZ group was treated with L-NAME, both SOD activity and superoxide anion content were additionally decreased indicating that the NOS-NO system was involved in the metabolism of superoxide anions. It is suggested that clinical and biochemical effects of NO strongly depend upon the pretreatment and might lead to a wrong impression of NO contradictory activity
It is expected that clinical recovery after surgically induced brain trauma is followed by molecular and biochemical restitution. Seven days after surgery, we investigated whether the plastic cannula implanted in the left brain ventricle of adult Wistar rats (n = 6-7), performed in pentobarbital anesthesia, could influence oxidative stress elements (superoxide anion and lipid peroxidation), as well as the antioxidative system (superoxide dismuthase-SOD). Also, we investigated whether nitric oxide (NO) is involved in these processes. Biochemical analyses was performed in the forebrain cortex, striatum and hippocampus. Clinical recovery was complete seven days after surgery. Thereafter, thirty minutes before decapitation, through the cannula, one group of rats received saline intracerebroventricularly (control group), and the treated group received Nω-nitro-L-arginine methyl ester (L-NAME). The third group was left unoperated and untreated. Before and after the treatments, rectal body temperature was measured. Compared to the untreated group the index of lipid peroxidation was increased in all three brain structures in the group that received saline (p<0.05 to 0.01). Application of L-NAME deteriorated it in the striatum and hippocampus (p<0.01 compared to the both other groups), but the value in the forebrain cortex was similar to the untreated group. Supeoxide anion level was decreased in the L-NAME treated group only in the striatum (p<0.01 compared to control and untreated groups), but SOD was increased in the hippocampus compared to the saline treated group (p<0.05). Seven days after brain surgery in pentobarbital anesthesia, recovery of biochemical disturbances was not parallel to clinical recovery. Long lasting biochemical changes are rather the consequence of brain injury than to pentobarbital anesthesia. In this experimental model, NO had protective effects, acting against lipid per oxidation in the striatum and hippocampus, but not in the forebrain cortex i. e. NO involvement in the free radical processes strongly depends on the observed brain region
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.