Leptin ameliorates testicular injury by altering expression of nitric oxide synthases in diabetic rats.

OBJECTIVES: We aimed to evaluate the effects of leptin and nitro-L-arginine methyl ester hydrochloride (L-NAME) on testicular damage and expression of nitric oxide synthase (NOS) types (neuronal, endothelial and inducible NOS) in streptozotocin (STZ) -induced diabetic and non-diabetic rats. METHODS: Testicular damage was evaluated histologically and expression of NOSs was evaluated immunohistochemically in testis. Plasma leptin level and blood glucose level were assessed. RESULTS: Blood glucose levels increased in all diabetic groups. L-NAME reduced it, but leptin had no effect. Three types NOS expression were shown in germ cells immunohistochemically. Increased eNOS and iNOS expression and decreased nNOS expression was detected in diabetic group. Testicular damage was observed in diabetic groups. Leptin ameliorated the damage by reducing iNOS expression and L-NAME partially prevented injury by supressing excessive NO production in diabetic rats. CONCLUSIONS: It can be suggested that leptin and L-NAME partially prevents testicular damage by ameliorating histopathological changes by stimulating and /or supressing three types of NOS expression in diabetic rats. Leptin exhibited its effects by reducing iNOS expression in diabetic rats. This is the first report demonstrating the relationship between leptin and nitric oxide in testicular tissue in STZ-induced diabetic rats (Fig. 3, Ref. 33).

Valeriana officinalis extract and 7-Nitroindozole ameliorated seizure behaviours, and 7-Nitroindozole reduced blood pressure and ECG parameters in pentylenetetrazole-kindled rats.

Nitric oxide (NO) is known to be a neuromodulator with dual proconvulsive and anticonvul- sive action. Valeriana officinalis (VAL) was previously believed to be antiepileptic, but is today known as a sedative and sleep regulator. Seizures may be associated with abnormal electrocardio- graphic changes and cardiac dysfunction arising from epilepsy may be related with neuronal nitric oxide (nNO). This study was aimed to investigate the effects of the neuronal nitric oxide synthase (nNOS) inhibitor 7-Nitroindazole (7-NI) and VAL on seizure behaviours and electrocar- diographic parameters in the pentylentetrazole (PTZ)-kindled seizure model. Wistar rats were randomised into saline control, PTZ-kindled, 7-NI, VAL and VAL+PTZ, 7-NI+PTZ and VAL+7-NI+PTZ groups. Latency, stage, frequency of seizures, blood pressure (BP), heart rate (HR) and corrected QT (QTc) values were evaluated. Frequency and stage of seizures, BP and HR increased, while seizure latency decreased and QTc was prolonged in the PTZ-kindled group. 7-NI and VAL had no effects on BP and HR variables under normal conditions, but ameliorated the seizure stage and frequency of seizures. 7-NI treatment also resulted in a reduction of the increased BP and prolonged QTc values observed in PTZ-kindled rats. Considering these results, QTc prolongation may be used as a predictor for recurrent seizures. 7-NI and VAL exhibited different effects on seizures and ECG variables. 7-NI shows potential as an anticonvulsant drug agent in epileptic patients with cardiac dysfunctions and those additional studies including in-vivo experiments are essential.

Crataegus tanacetifolia leaf extract prevents L-NAME-induced hypertension in rats: a morphological study.

Crataegus (hawthorn) has long been used as a folk medicine all around the world. Most of the studies with Crataegus species focus on effects on heart failure and cardiovascular disease. The pharmacological effects of Crataegus have been attributed mainly to the content of flavonoids, procyanidin, aromatic acid and cardiotonic amines. The present study investigated the blood pressure and the structure of the coronary arterial wall of L-NAME-induced hypertensive rats given an aqueous leaf extract of C. tanacetifolia (100 mg/kg), for 4 weeks via gavage. It was observed that C. tanacetifolia, especially the hyperoside fraction, prevented L-NAME-induced hypertension in rats and had beneficial effects on the cardiovascular system.