Neuroprotective effect of sumatriptan in pentylenetetrazole-induced seizure is mediated through N-methyl-D-aspartate/nitric oxide and cAMP response element-binding protein signaling pathway

The potential role of nitric oxide in the anticonvulsant effects of betulin in pentylenetetrazole (PTZ)-induced seizures in mice

Epilepsy poses a significant challenge, especially for drug-resistant cases, necessitating novel treatment avenues. This study explores the potential interplay between nitric oxide (NO) and the anticonvulsant effects of betulin, a triterpene with promising neuroprotective properties. While betulin exhibits anticonvulsant effects, the specific involvement of NO remains inadequately understood, constituting a pivotal gap in current knowledge. One hundred NMRI mice were randomly assigned to diverse treatment groups, with seizures induced by pentylenetetrazol (PTZ). Parameters such as seizure threshold, nitrite levels, total antioxidant capacity (TAC), malondialdehyde (MDA) levels, and iNOS/nNOS gene expressions were assessed. Betulin significantly increased seizure thresholds and mitigated PTZ-induced NO levels. These findings suggest a potential modulation of NO-related pathways, emphasizing betulin's anti-inflammatory and antioxidant attributes. The study sheds light on betulin's multifaceted impact on oxidative stress, NO regulation, and iNOS/nNOS gene expressions. The ability of betulin to suppress iNOS/nNOS gene expressions, leading to reduce NO production, underscores its potential as an anticonvulsant.

Duality in response of intracranial vessels to nitroglycerin revealed in rats by imaging photoplethysmography

Among numerous approaches to the study of migraine, the nitroglycerin (NTG) model occupies a prominent place, but there is relatively insufficient information about how NTG affects intracranial vessels. In this study we aim to assess the effects of NTG on blood-flow parameters in meningeal vessels measured by imaging photoplethysmography (iPPG) in animal experiments. An amplitude of the pulsatile component (APC) of iPPG waveform was assessed before and within 2.5 h after the NTG administration in saline (n = 13) or sumatriptan (n = 12) pretreatment anesthetized rats in conditions of a closed cranial window. In animals of both groups, NTG caused a steady decrease in blood pressure. In 7 rats of the saline group, NTG resulted in progressive increase in APC, whereas decrease in APC was observed in other 6 rats. In all animals in the sumatriptan group, NTG administration was accompanied exclusively by an increase in APC. Diametrically opposite changes in APC due to NTG indicate a dual effect of this drug on meningeal vasomotor activity. Sumatriptan acts as a synergist of the NTG vasodilating action. The results we obtained contribute to understanding the interaction of vasoactive drugs in the study of the headache pathophysiology and methods of its therapy.

Protection against Morphine-Induced Inhibitory Avoidance Memory Impairment in Rat by Curcumin: Possible Role of Nitric Oxide/ cAMP-Response Element Binding Protein Pathway

BACKGROUND

Although a substantial body of research suggests curcumin (CUR) has the preventive potential in memory impairment, the mechanism by which CUR prevents memory loss is still being investigated. This study employs an inhibitory avoidance (IA) model to investigate whether CUR can prevent morphine (Mor)-induced memory impairment as well as the possible role of cAMP-response element binding (CREB) protein, and nitric oxide (NO) signaling in this mechanism.

METHODS

This experimental study was conducted at the Animal Lab of the Physiology Research Center, Kashan University of Medical Sciences (Kashan, Iran) in 2018. Forty rats were randomly divided into four groups: control, CUR (pretreatment gavage of CUR [10 mg/Kg] for 35 days), Mor (7.5 mg/Kg, i.p.), and CUR+Mor (n=10 per group). Following the evaluation of the IA memory and locomotor activity of the animals, the CREB protein expression in the hippocampus and NO metabolites (NOx) level in the brain tissue were also investigated. The data were analyzed using Sigmaplot software (version 14.0) by using the ANOVA, Kruskal-Wallis, Holm-Sidak, and Dunn's post hoc tests. P<0.05 was considered to be statistically significant.

RESULTS

In the Mor group, the IA memory of the rats was significantly impaired (P=0.001). CUR prevented the Mor-induced IA memory impairment (P=0.075). While the Mor treatment decreased the phosphorylated CREB (p-CREB) expression, the CUR+Mor cotreatment increased p-CREB expression (P=0.010). Nevertheless, the Mor treatment increased the total CREB expression (P=0.010). The NOx concentration in the brain tissue was decreased following the Mor treatment (P=0.500) but increased after the CUR+Mor cotreatment (P=0.001).

CONCLUSION

The present findings suggest that CUR prevents the memory impairment of rats, possibly through NO and its downstream CREB signaling.