Endogenous opiates and behavior: 2007.

Involvement of the brain renin–angiotensin system (RAS) in the neuroadaptive responses induced by amphetamine in a two-injection protocol

Purpose: As an angiotensin converting enzyme (ACE) inhibitor, the effects of captopril on inflammation has been previously examined. Captopril has been shown to have anti-inflammatory and antioxida...

The effect of captopril on lipopolysaccharide-induced lung inflammation

The dopaminergic mesolimbic system is considered to be crucial in rewarding actions of opiates. Recent studies have suggested probable interaction between the renin-angiotensin and mesolimbic dopaminergic systems. The present study was undertaken to investigate the effects of Ang II and captopril injection into VTA on morphine self-administration. Male Wistar rats were initially trained to receive small pellets of food by pressing the active lever in self-administration apparatus. The animals were divided into 4 groups (saline, morphine, captopril and Ang II) and were placed in self-administration apparatus and allowed to self-administer morphine (0.5 mg per infusion all test groups) or saline (saline group) during consecutive days, for 2 h/sessions. Captopril (30 μg) and Ang II (0.25 nmol) were injected into the VTA in the corresponding groups before each session. The numbers of active and passive levers pressed in each group have been recorded. The number of active lever pressing of morphine group was s...

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Effects of microinjection of angiotensin II and captopril to VTA on morphine self-administration in rats.

In the present study, the effects of tamoxifen on pentylenetetrazole (PTZ)-induced repeated seizures and hippocampal neuronal damage in ovariectomized rats were investigated. Thirty seven virgin female Wistar rats were divided to: (1) control, (2) sham-PTZ, (3) sham-PTZ-tamoxifen (sham-PTZ-T), (4) Ovariectomized -PTZ (OVX-PTZ) and (5) OVX-PTZ-tamoxifen (OVX-PTZ-T) groups. The animals of groups 3 and 5 were injected by tamoxifen (10 mg/kg) on 7 consecutive days. After 7 days of tamoxifen injection, they also were then injected by tamoxifen 30 min prior each PTZ injection. PTZ (40 mg/kg) was injected on 6 consecutive days and the animal behaviors were observed for 60 min. The histological methods were then used to determine dark neurons in hippocampus. A significant decrease in the seizure score was seen in OVX-PTZ group compared to Sham-PTZ. The animals of OVX-PTZ-T group had a significant higher seizure score compared to OVX-PTZ group. The dark neurons in DG of OVX group were lower than sham group (p<0.01). The numbers of dark neurons in CA1 area of OVX-PTZ-T group was higher than OVX-PTZ group (p<0.05) compared to control, the numbers of dark neurons in CA3 area showed a significant increase in Sham-PTZ and OVX-PTZ group (p<0.05 and p<0.01 respectively). Dark neurons in OVX-PTZ-T group were higher than OVX-PTZ group (p<0.05). It is concluded that pretreatment of the ovariectomized rats by tamoxifen increased PTZ-induced seizure score and dark neurons. It might be suggested that tamoxifen has agonistic effects for estrogen receptors to change the seizure severity.

Tamoxifen Mimics the Effects of Endogenous Ovarian Hormones on Repeated Seizures Induced by Pentylenetetrazole in Rats

The effects of captopril and Ang II on morphine-induced conditioned place preference (CPP) and morphine self-administration in male Wistar rat were investigated. In CPP experiment, injection of captopril before test significantly decreased the difference of the time spent in compartment A between pre- and post-conditioning compared to morphine group. In self- administration experiment number of active lever pressing was significantly greater than passive in morphine group. In captopril group number of active lever pressing was significantly lower than morphine group however, there was not significant difference between active and passive lever pressed number. The results showed that captopril significantly decreased morphine-induced conditional place preference and morphine self-administration but the effect of Ang II was not significant. It can be concluded that RAS may have a role in rewarding properties of morphine.

http://nopr.niscair.res.in/bitstream/123456789/5326/1/IJEB%2045%289%29%20770-777.pdf

Effects of angiotensin II and captopril on rewarding propreties of morphine

Summary In present study probable effects of L/ arginine on morphine tolerance in ovariectomized rats was investigated. 8 weeks after ovariectomy, rats were divided into test groups, including Tolerant and Tolerant+ L/Arginine(10, 50 and 200 mg/kg ) groups. Morphine tolerance was induced by daily injection of 20 mg/kg morphine during 4 consecutive days. Animals of groups 2, 3 and 4 were simultaneously treated with 10, 50 and 200mg/kg L/Arginine, respectively. Hotplate test was carried out in 5th day as a base record, then the animals received 5 mg/kg morphine and antinociceptive effect was evaluated every 10 min. The base time of Tolerant group was lower than Tolerant + L/ Arginine 10, 50 and 200 mg/kg groups. Analyzing by repeated measure ANOVA showed that reaction time after last injection of 5 mg/kg morphine in tolerant group was lower than all 3 Tolerant + L/Arginine groups .This implies that L/Arginine reduces morphine tolerance in ovariectomized rats.

Habib Allah Nemati Karimooy

Papers

Effects of angiotensin II and captopril on rewarding propreties of morphine

Effect of largiie, theitric oxide precurs or, omorphie tolerace iovariectomized rats