Effect of oleuropein on morphine-induced hippocampus neurotoxicity and memory impairments in rats.

Oleuropein, as an olive leaf extract antioxidant polyphenol, has been reported to be a free radical scavenger. This study was done to investigate the effects of oleuropein, against morphine-induced hippocampus neurotoxicity and memory impairment in rats. The Morris water maze (MWM) test was used to assess the effect of oleuropein (5, 15, and 30 mg/kg, i.p., co-administrated with morphine) on spatial learning and memory of male Wistar rats which were treated with morphine sulfate (45 mg/kg, s.c., 4 weeks). In order to evaluate the cleaved caspase-3, Bax, and Bcl2 protein expression (as biochemical markers of apoptosis) in CA1 area of hippocampus tissue, the western blot test was used. Also, to evaluate the oxidative stress status of hippocampus CA1 area tissue, the malondialdehyde (MDA) level, superoxide dismutase (SOD) activity, and glutathione peroxidase (GPx) activity were assessed. The data showed that oleuropein treatment (15 and 30 mg/kg) improves the spatial learning and memory impairments in morphine-treated animals. Also, oleuropein treatment decreased the apoptosis and oxidative stress levels in the hippocampus CA1 area of morphine-treated rats. Oleuropein can prevent the spatial learning and memory impairments in morphine-treated rats. Molecular mechanisms underlying the observed effects could be at least partially related to the inhibition of neuronal apoptosis and oxidative stress in the hippocampus CA1 area of morphine-treated rats.

The role of locus coeruleus nucleus TRPV1 receptors in the development and expression of morphine dependence.

OBJECTIVES: This study investigated the role of locus coeruleus (LC) nucleus TRPV1 receptors (TRPV1r) in the expression and development of morphine physical dependence by intra-LC administration of AMG9810 (selective TRPV1r antagonist) in male Wistar rats. MATERIALS AND METHODS: For assessing the development of morphine dependence, AMG9810 (0.03 and 0.3 mM in 10% DMSO, 0.2 µl; intra-LC microinjection) was administered before each morphine administration for seven continues days (once daily; 6, 16, 26, 36, 46, 56, and 66 mg/kg; sc). Furthermore, for evaluating the expression of morphine dependence, a single dose of AMG9810 (0.03 and 0.3 mM in 10% DMSO, 0.2 µl; intra-LC microinjection) was administered to morphine-dependent rats on day 8 of the experiment. RESULTS: Obtained data demonstrated that co-administration of TRPV1r antagonist with morphine reduced the development of morphine withdrawal syndrome somatic signs induced by naloxone. Moreover, single intra-LC administration of TRPV1r antagonist on the final day of the examination period significantly decreased the expression of some signs of morphine withdrawal in rats. CONCLUSION: The results showed that LC TRPV1r might be participating in the expression and development of morphine dependence.

The Role of Vasodilator Receptors of Renin-angiotensin System on Nitric Oxide Formation and Kidney Circulation after Angiotensin II Infusion in Renal Ischemia/Reperfusion Rats.

BACKGROUND: Nitric oxide (NO) as a vasodilator factor has renoprotective effect against renal ischemia. The balance between angiotensin II (Ang II) and NO can affect kidney homeostasis. The aim of this study was to determine NO alteration in response to renin-Ang system vasodilator receptors antagonists (PD123319; Ang II type 2 receptor antagonist and A779; Mas receptor antagonist) in renal ischemia/reperfusion injury (IRI) in rats. MATERIALS AND METHODS: Sixty-three Wistar male and female rats were used. Animals from each gender were divided into four groups received saline, Ang II, PD123319 + Ang II, and A779 + Ang II after renal IRI. Renal IRI induced with an adjustable hook. Blood pressure and renal blood flow (RBF) measured continuously. The nitrite levels were measured in serum, kidney, and urine samples. RESULTS: In female rats, the serum and kidney nitrite levels increased significantly by Ang II (P < 0.05) and decreased significantly (P < 0.05) when PD123319 was accompanied with Ang II. Such observation was not seen in male. Ang II decreased RBF significantly in all groups (P < 0.05), while PD + Ang II group showed significant decrease in RBF in comparison with the other groups in female rats (P < 0.05). CONCLUSION: Males show more sensibility to Ang II infusion; in fact, it is suggested that there is gender dimorphism in the Ang II and NO production associated with vasodilator receptors.