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Introduction: The sympathetic nervous system and the renin-angiotensin system (RAS) are the most pivotal vasoactive systems in regulating renal hemodynamics. The main objective of this study was to determine the role of the angiotensin II (Ang II) type 1 receptor (AT1R) antagonist on renal hemodynamic responses to Ang 1-7 infusion in innervated and denervated male and female rats. Methods: Male and female Wistar rats underwent unilateral nephrectomy. Four weeks later, they were divided into two groups: innervated and acutely denervated groups. Subsequently, the anesthetized and catheterized rats in both groups were treated with saline as a vehicle and losartan infusion. Mean arterial pressure (MAP), renal blood flow (RBF), renal perfusion pressure (RPP), and renal vascular resistance (RVR) responses to Ang 1-7 (100, 300, and 1000 ng kg−1 min−1 ) were then measured at controlled RPP. Results: Basal MAP, RPP, RBF, and RVR did not show significant differences between the intact and denervated groups. Losartan significantly decreased MAP, RPP, and RVR in both innervated and denervated male and female rats (P<0.001), while RBF increased only in innervated and denervated female rats (P<0.004). However, following Ang 1-7 administration, the RBF response to Ang 1-7 infusion differed significantly between intact and denervated male rats treated with losartan (P<0.04). This response was not observed in female rats. Conclusion: These data suggest a synergistic effect of losartan and Ang 1-7 on increased RBF in the presence of renal sympathetic nerves in male rats. [ABSTRACT FROM AUTHOR]

Background and purpose: Renal hemodynamics is influenced by renal sympathetic nerves and the reninangiotensin system. On the other hand, renal sympathetic denervation impacts kidney weight by affecting renal hemodynamics. The current study evaluated the role of the Mas receptor on renal hemodynamic responses under basal conditions and in response to angiotensin II (Ang II) in chronic renal sympathectomy in female and male rats. Experimental approach: Forty-eight nephrectomized female and male rats were anesthetized and cannulated. Afterward, the effect of chronic renal sympathectomy was investigated on hemodynamic parameters such as renal vascular resistance (RVR), mean arterial pressure (MAP), and renal blood flow (RBF). In addition, the effect of chronic sympathectomy on kidney weight was examined. Findings/Results: Chronic renal sympathectomy increased RVR and subsequently decreased RBF in both sexes. Renal perfusion pressure also increased after sympathectomy in male and female rats, while MAP did not change, significantly. In response to the Ang II injection, renal sympathectomy caused a greater decrease in RBF in all experimental groups, while it did not affect the MAP response. In addition, chronic sympathectomy increased left kidney weight in right nephrectomized rats. Conclusion and implications: Chronic renal sympathectomy changed systemic/renal hemodynamics in baseline conditions and only renal hemodynamics in response to Ang II administration. Moreover, chronic sympathectomy increased compensatory hypertrophy in nephrectomized rats. These changes are unaffected by gender difference and Mas receptor blocker. [ABSTRACT FROM AUTHOR]

The denervation or activation of the sympathetic nerve in the kidney can affect renal hemodynamics. The sympathetic nervous system regulates the physiological functions of the kidneys. Stimulation of sympathetic efferent nerves affects various parameters related to renal hemodynamics, including sodium excretion, renin secretion, and renal blood flow (RBF). Hence, renal sympathetic fibers may also play an essential role in regulating systemic vascular resistance and controlling blood pressure. In the absence of renal nerves, the hemodynamics response to stimuli is negligible or absent. The effect of renal sympathetic denervation on RBF is dependent on several factors such as interspecies differences, the basic level of nerve activity in the vessels or local density of adrenergic receptor in the vascular bed. The role of renal denervation has been investigated therapeutically in hypertension and related disorders. Hence, the dynamic impact of renal nerves on RBF enables using RBF dynamic criteria as a marker for renal denervation therapy. [ABSTRACT FROM AUTHOR]

Background: The dorsal raphe nucleus (DRN) influences a wide range of behavioral and reward function. In this study, we evaluated electrical stimulation and inactivation of DRN on morphine conditioned place preference (CPP). Methods: The rats were anesthetised (n = 7 for each group) and the electrode and cannula were implanted into the DRN by stereotaxic instrument. Electrical stimulation (100µA) and reversible inactivation by lidocaine were induced into DRN and then morphine-induced CPP was investigated. Results: The stimulation of DRN in combination with effective dose of morphine showed a significant decrease only on expression phases 20s (SD 33.7) when compared with morphine group 119.85s (SD 23.7) (One way ANOVA, Tukey's; P = 0.036). Also, this stimulation in combination with ineffective dose of morphine showed a significant increase only on acquisition phases 67.5s (SD 41.2) of CPP compared with morphine group -46s (SD 18.51) (P = 0.034). Also, there were not significant differences in inactivation of DRN by lidocaine on different phase of CPP (P = 0.091). Conclusion: It is possible that electrical stimulation of the DRN with changes in concentration of serotonin or involving other transmitters such as glutamate and gamma amino butyric acid (GABA) would be involved to these changes of CPP. [ABSTRACT FROM AUTHOR]

Introduction. Opiates are traditionally used for treatment of some acute heart disorders. There are only few reports on the effects of long-term treatment of cardiovascular diseases with morphine. This study aimed to investigate the effects of chronic low-dose morphine use on the cardiovascular system in two-kidney one-clip (2K1C) hypertensive rats.Materials and Methods. Male Wistar rats were divided into two groups as the sham and 2K1C groups and each group was further subdivided into saline and morphine treatment subgroups. Blood pressure, heart rate, plasma rennin activity, serum nitric oxide concentration, and baroreflex sensitivity were measured.Results. Morphine significantly attenuated systolic blood pressure, diastolic blood pressure, and mean arterial pressure in the 2K1C animals. In addition, morphine decreased plasma rennin activity in the 2K1C group. Serum concentrations of nitric oxide were also decreased, and morphine prevented the reduction of nitric oxide. The baroreflex sensitivity was also improved following morphine administration in the 2K1C group. Conclusions. According to the results presented in this study, chronic administration of low-dose morphine reduces regulated hypertension in the 2K1C rats, probably via a nitric oxide-dependent pathway. [ABSTRACT FROM AUTHOR]

Background: Spathe of phoenix dactylifera is hard-covering envelope of date palm which is mentioned as a nerve relief in ancient medicine books. In this experiment, three extract doses used in sleeping time, sedative efficacy, and electroencephalography (EEG) protocol to show different aspects of extract effects on sleep., Materials and Methods: In three sleeping time, anesthesia time and EEG experiment protocols test group containing three extract doses (62.5, 125, and 250 mg/kg) were compared with saline control group, and in sleeping time experiment control group contained intact, midazolam, and saline group to detail more in behavioral Angel method., Results: Three extract doses increased sleeping time when compared with saline control group ( P < 0.05). In evaluated sedative efficacy, two 125 and 250 mg/kg doses increased anesthesia and showed sedative effect ( P < 0.05). In EEG experiment, dose 125 mg/kg increased delta waves and decreased high-frequency waves of alpha and beta. In addition, there were significant decreases in alpha waves of 62.5 and 250 mg/kg doses., Conclusion: Although all three doses increased sleeping time, dose 125 mg/kg is more efficient for deep and relaxing sleep and suits more for related researches., Competing Interests: There are no conflicts of interest.

Background: Sneezing transiently elevates cerebral blood flow. We speculated that induced sneezing, following embolism would restore arterial flow, thereby diminishing infarct volume and improving neurological deficits., Materials and Methods: Male rats were subjected to middle cerebral artery occlusion (MCAO) using prepared clots (embolization) and randomized into four equal groups as follows: (1) pre-MCAO-induced sneezing (PRMIS), (2) post-MCAO-induced sneezing (POMIS), and (3) pre- and POMIS (PRPOMIS) and the control group (eight rats per group). In the treatment groups, rats' sneezing episodes were induced before MCAO in PRMIS group or before regaining consciousness from surgical anesthesia in other treatment groups by cutting their whiskers during their anesthesia and subsequently inserted them into the rats' nostrils. Infarct volume was evaluated by 2, 3, 5-triphenyl tetrazolium chloride staining, and neurological deficits and brain edema were assessed by Bederson scale deficit scores 24-h post-MCAO., Results: The infarct volume and brain edema reduced and neurological deficits improved in the induced sneezing groups as compared with the MCAO control group. Compared to the control group, the highest improvements in the infarct volume and neurological deficits were seen in the PRPOMIS group, and POMIS group showed the most significant differences concerning the results of both ischemic and nonischemic brain edema. The highest protective effect was observed in the central region of the MCA territory., Conclusions: The reduction in ischemia-induced brain injury, brain edema, and neurological deficits by sneezing suggest that brief episodes of acute hypertension after stroke can increase blood flow to the ischemic area and improve recovery., Competing Interests: There are no conflicts of interest.

Background: Chronic stress adversely influences brain functions while crocin, as an effective component of saffron, exhibits positive effects on memory processes. This study investigated the effects of different doses of crocin on the improvement of learning and memory as well as corticosterone (CORT) levels in the hippocampus and frontal cortex of rats subjected to chronic stress., Materials and Methods: Forty male rats were randomly allocated to five different groups ( n = 8): Control, sham; stress (6 h/day for 21 days) groups, and two groups receiving daily intraperitoneal injections of one of two doses (30 and 60 mg/kg) of crocin accompanied by 21 days of restraint stress. Latency was evaluated as a brain function using the passive avoidance test before and one-day after a foot shock. CORT levels were measured in the homogenized hippocampus and frontal cortex., Results: Results revealed that chronic stress had a significantly ( P < 0.01) negative effect on memory. Crocin (30 and 60 mg/kg), however, gave increase to significantly ( P < 0.01 and P < 0.05; respectively) improved memory functions in the stressed rats. Furthermore, the CORT levels in the hippocampus and frontal cortex declined significantly ( P < 0.05) in the stress group compared to the control. Only a crocin dose of 30 mg/kg was observed modulate significantly ( P < 0.05) the CORT levels in the hippocampus and frontal cortex in the stressed group., Conclusions: It was found that the lower crocin dose (30 mg/kg) had more beneficial effects than its higher (60 mg/kg) dose on learning and memory under chronic stress conditions. Moreover, it was speculated that different doses of crocin act on different neurotransmitters and biochemical factors in the brain., Competing Interests: There are no conflicts of interest.

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 β-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 β-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 β-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 β-adrenergic receptor of NTS in BRS.

Background: We investigated coronary angiogenesis and serum vascular endothelial growth factor (VEGF) and its soluble receptor-1 (sFlt-1) concentrations in two-kidney one-clip (2K1C) hypertensive rats before and after reversal of hypertension., Methods: THE ANIMAL GROUPS WERE: (i) sham-clipped for 12 weeks; (ii) 2K1C for 12 weeks; (iii) sham-clipped for 12 weeks and unclipped for 12 weeks; and (iv) 2K1C for 12 weeks and unclipped for 12 weeks. Blood samples were taken before experiments and after clipping and unclipping; capillary density was also evaluated., Results: Our results showed that blood pressure in hypertensive animals was higher than sham group (175 ± 10 vs. 110.3 ± 11.3 mmHg; p < 0.05). Unclipping significantly reduced blood pressure in hypertensive rats (p < 0.05). Serum VEGF and sFlt-1 levels in hypertensive group were significantly lower than sham group (VEGF: 74.36 ± 5.85 vs. 104.07 ± 7.75 pg/ml; sFlt-1: 426.67 ± 25.74 vs. 690.76 ± 41.14 pg/ml, respectively; p < 0.05). Unclipping in hypertensive animals increased serum VEGF and sFlt-1 concentrations (VEGF: 93.65 ± 8.61 vs. 74.36 ± 5.85 pg/ml; sFlt-1: 742.05 ± 79.23 vs. 426.67 ± 25.74 pg/ml, respectively; p < 0.05). In hypertensive animals, capillary density in the heart was higher than sham group, non-significantly (p > 0.05) and after unclipping, it reached to sham group level., Conclusions: It seems that changes in capillary density and serum VEGF and sFlt-1 concentrations in renovascular hypertension are reversible by removing the cause of hypertension and it shows the importance of early diagnosis and treatment of hypertension in clinical condition.