The standardized extract of Nigella sativa and its major ingredient, thymoquinone, ameliorates angiotensin II-induced hypertension in rats.

Background This study investigated the effect of hydroalcoholic extract of Nigella sativa (N. sativa) and its active component, thymoquinone (TQ) on hypertension induced by angiotensin II (AngII), the main product of renin-angiotensin system (RAS). Methods Seven animal groups (n=7 for each group) were used as follows: (1) control, (2) AngII (300 ng/kg), (3) AngII+losartan (Los; 10 mg/kg), (4) TQ (40 mg/kg)+AngII, and (5-7) three doses of N. sativa (200, 400, and 600 mg/kg)+AngII. Los and AngII were injected intravenously; TQ and extracts were injected intraperitoneally. In TQ and N. sativa-treated groups, 30 min after injection of the extract and TQ, AngII was injected. Cardiovascular parameters were recorded by power lab system after cannulation of femoral artery. The maximum changes (∆) of systolic blood pressure (SBP), mean arterial pressure (MAP), and heart rate (HR) were calculated and used for statistical analysis. Results AngII significantly increased maximal ∆SBP, ∆MAP, and ∆HR compared with the control (p<0.001), and these effects significantly were blunted by Los. TQ and two higher doses (400 and 600 mg/kg) of N. sativa significantly could antagonize effect of AngII on ∆SBP, ∆MAP (p<0.05 to p<0.001). AngII-induced changes of HR are also significantly decreased by TQ and dose 600 mg/kg of extract (p<0.01 and p<0.05, respectively). Conclusions The N. sativa and its component TQ have the beneficial effect on hypertension probably due to attenuation cardiovascular effects of AngII.

Involvement of ß-adrenergic receptor of nucleus tractus solitarius in changing of baroreflex sensitivity by estrogen in female rats.

BACKGROUND: Arterial baroreflex (ABR) is an important factor in preventing of blood pressure fluctuations that determined by baroreflex sensitivity (BRS). Estrogen is an ovarian hormone that has influence on ABR. The mechanism of this effect of estrogen unknown and may be mediated by ß-adrenergic receptor of nucleus tractus solitarius (NTS), an important area in regulation of baroreflex. Therefore, in this study changing of BRS by estrogen after blockade ß-adrenergic receptor of NTS in ovariectomized rats (Ovx) and Ovx treated with estrogen (Est) was examined. MATERIALS AND METHODS: After ovariectomy, all female rats divided to Ovx and Ovx + Est groups and two series of experiments were performed. In the first experiment, phenylephrine was [intravenously, IV] injected in both the Ovx and Ovx + Est groups, and mean arterial pressure (MAP), heart rate (HR), and BRS were evaluated (n = 8 for each group). In the second experiment, each of Ovx and Ovx + Est groups divided into saline and propranolol (pro) groups, saline and pro stereotaxically were microinjected into NTS, respectively. Further, phenylephrine (IV) was injected in all groups and BRS was evaluated. RESULTS: BRS significantly increased in estrogen-treated groups (Ovx + Est) compared to Ovx groups (P < 0.01). The blockade ß-adrenergic receptor of NTS by pro did not significantly changed BRS in both Ovx and Ovx + Est groups. CONCLUSION: We concluded that there aren't any intraction between estrogen and ß-adrenergic receptor of NTS in BRS.

Pharmacological study of cholinergic system on cardiovascular regulation in the cuneiform nucleus of rat.

In the present study the effect of cholinergic system of Cuneiform nucleus (CnF) on central regulation of cardiovascular system was investigated. Two doses of acetylcholine (Ach; 90 and 150 nmol), atropine (3 and 9 nmol) and hexamethonium (Hexa; 100 and 300 nmol) were microinjected into the CnF. The maximum changes of MAP and HR were compared with control group (independent t-test). Both doses of Ach significantly decreased MAP but had no significant effect on HR. Administration of atropine and Hexa by themselves did not alter the MAP or HR. However, both doses of atropine and higher dose of Hexa significantly attenuated the hypotensive effect of Ach with no significant effect on HR. Our results suggest the involvement of CnF cholinergic system only on central blood pressure regulation that strongly mediated by muscarinic receptors.

Estrogen-dependent effect of soy extract on pentylenetetrazole-induced seizures in rats.

OBJECTIVE: To study the different effects of soy extract on pentylenetetrazole (PTZ)-induced seizures in the presence and absence of ovarian hormones in rats, and the gender-dependent differences in the effects of phytoestrogens on behavior. METHODS: Male and female Wistar rats were randomly divided into nine groups with eight in each, namely, male-saline (M-saline), male-low-dose soy (M-LDS), male-high-dose soy (M-HDS), sham-saline (Sh-saline), sham-low-dose soy (Sh-LDS), sham-high-dose soy (Sh-HDS), ovariectomized-saline (OVX-saline), ovariectomized-low-dose soy (OVX-LDS) and ovariectomized-high-dose soy (OVX-HDS). The rats of groups 7 to 9 were ovariectomized under ketamine anesthesia. The rats of groups 2, 5 and 8 were treated by 20 mg/kg of soy extract while the animals of groups 3, 6 and 9 received 60 mg/kg of soy extract for two weeks. In groups 1, 4 and 7, saline was injected instead of soy extract. The animals were then injected by a single dose of PTZ (90 mg/kg body weight, intraperitoneally) and placed in a plexiglas cage and the latency to minimal clonic seizure (MCS) and generalized tonic-clonic seizure (GTCS) was recorded. RESULTS: Both MCS and GTCS latency in M-LDS and M-HDS groups was significantly lower than that in M-saline group (P<0.05 or P<0.01). Treatment for female sham rats by soy extract did not affect MCS and GTCS latency. The animals of OVX-LDS and OVX-HDS groups had lower MCS and GTCS latency in comparison with OVX-saline group (P<0.05 or P<0.01). CONCLUSION: It is concluded that the phytoestrogens of soy affect seizure severity induced by PTZ, but their effects are different in the presence or absence of ovarian hormones. However, further studies are necessary to be done.

Estrogen-dependent effect of soy extract on pentylenetetrazole-induced seizures in rats / 中西医结合学报

To study the different effects of soy extract on pentylenetetrazole (PTZ)-induced seizures in the presence and absence of ovarian hormones in rats, and the gender-dependent differences in the effects of phytoestrogens on behavior.