scholarly journals Pharmacological Analysis of the Enhanced Pressor Response to Central Cholinergic Stimulation in Spontaneously Hypertensive Rats

1990 ◽  
Vol 54 (2) ◽  
pp. 105-112 ◽  
Author(s):  
Jerry J. BUCCAFUSCO ◽  
Nevine F. MAKARI ◽  
Alan C. HAYS
2008 ◽  
pp. 137-139
Author(s):  
S Čačányiová ◽  
F Kristek ◽  
J Kuneš ◽  
J Zicha

We investigated the effect of pertussis toxin (PTX) on hypotensive response induced by acetylcholine (ACh) and bradykinin (BK) and on noradrenaline (NA)-induced pressor response in spontaneously hypertensive rats (SHR). Fifteenweek-old Wistar rats and age-matched SHR were used. Half of SHR received PTX (10 µg/kg/i.v.) and the experiments were performed 48 h later. After the anesthesia the right carotid artery was cannulated in order to record blood pressure (BP). The hypotensive response to ACh was enhanced in SHR compared to Wistar rats. After pretreatment of SHR with PTX the hypotensive response to ACh was reduced compared to untreated SHR and it was also diminished in comparison to Wistar rats. Similarly, the hypotensive response to BK was also decreased after PTX pretreatment. The pressor response to NA was increased in SHR compared to Wistar rats. NA-induced pressor response was considerably decreased after PTX pretreatment compared to untreated SHR. In conclusion, the enhancement of hypotensive and pressor responses in SHR was abolished after PTX pretreatment. Our results suggested that the activation of PTXsensitive inhibitory Gi proteins is involved in the regulation of integrated vasoactive responses in SHR and PTX pretreatment could be effectively used for modification of BP regulation in this type of experimental hypertension.


Hypertension ◽  
2017 ◽  
Vol 70 (suppl_1) ◽  
Author(s):  
Rodrigo O Maranon ◽  
Carolina Dalmasso ◽  
Chetal N Patil ◽  
Jane F Reckelhoff

Men have higher blood pressure (BP) than premenopausal women. Pressor response to oxidative stress may be a major contributor to the sex difference in BP control. Mitochondrial oxidative stress is associated with hypertension; however, whether mitochondrial oxidative stress plays a role in the sex difference in BP is unknown. In the present study, we tested the hypothesis that mitochondrial oxidative stress contributes to the sex difference in BP regulation in spontaneously hypertensive rats (SHR). Young intact (iYMSHR) and castrated males (cYMSHR), and females SHR (YFSHR) (3 mos of age) were implanted with radiotelemeters, and after a 4 day baseline BP, were treated with mitoTempo (0.75 mg/kg/d, sc minipumps), a specific scavenger of mitochondrial superoxide, for 7 days. Following 10 days washout of mito-tempo, rats were treated with Tempol (30 mg/kg/day, po drinking water) for 7 days. iYMSHR have higher blood pressure (by telemetry) than cYMSHR and YFSHR (148±1 mmHg, n=5, vs 132±1 mmHg, n=5, and 139±1 mmHg, n=5; p<0.01, respectively). MitoTempo reduced BP by 6% in iYMSHR (147±1 vs 139±1, n=5; p<0.05) compared to females (3%: 139±1 vs 136±1; n=5; p: NS) and castrated males (4.5%: 132±1 vs 126±1, n=5; p<0.05). After 10 days washout, tempol reduced BP only in iYMSHR (144±1 vs 130±1 mmHg, n=5; p<0.05). Our results suggest that mitochondrial oxidative stress may contribute to BP regulation in male SHR, but has no effect in females. The data also suggest that the presence of testosterone is necessary for the pressor response to oxidative stress in males since Tempol had no effect on BP in castrated males. Further studies examining the effect of steroid hormones and mitochondria in BP regulation are necessary to elucidate the importance of mitochondrial oxidative stress on sex difference of hypertension.


1999 ◽  
Vol 276 (3) ◽  
pp. R872-R879 ◽  
Author(s):  
Donella B. Sampey ◽  
Louise M. Burrell ◽  
Robert E. Widdop

The aim of the present study was to determine the receptor subtype involved in arginine vasopressin (AVP)-induced modulation of baroreflex function in spontaneously hypertensive rats (SHR) and Wistar-Kyoto (WKY) rats using novel nonpeptide AVP V1- and V2-receptor antagonists. Baroreceptor heart rate (HR) reflex was investigated in both SHR and WKY rats which were intravenously administered the selective V1- and V2-receptor antagonists OPC-21268 and OPC-31260, respectively. Baroreflex function was assessed by obtaining alternate pressor and depressor responses to phenylephrine and sodium nitroprusside, respectively, to construct baroreflex curves. In both SHR and WKY rats baroreflex activity was tested before and after intravenous administration of vehicle (20% DMSO), OPC-21268 (10 mg/kg), and OPC-31260 (1 and 10 mg/kg). Vehicle did not significantly alter basal mean arterial pressure (MAP) and HR values or baroreflex function in SHR or WKY rats. The V1-receptor antagonist had no significant effect on resting MAP or HR values or on baroreflex parameters in both groups of rats, although this dose was shown to significantly inhibit the pressor response to AVP (5 ng iv; ANOVA, P < 0.05). In SHR but not WKY rats the V2-receptor antagonist significantly attenuated the gain (or slope) of the baroreflex curve (to 73 ± 3 and 79 ± 7% of control for 1 and 10 mg/kg, respectively), although AVP-induced pressor responses were also attenuated with the higher dose of the V2-receptor antagonist. These findings suggest that AVP tonically enhances baroreflex function through a V2 receptor in the SHR.


1988 ◽  
Vol 46 ◽  
pp. 128
Author(s):  
Yoshiko Masubuchi ◽  
Toshio Kumai ◽  
Taiichiro Ohno ◽  
Masami Tanaka ◽  
Minoru Watanabe ◽  
...  

1995 ◽  
Vol 69 (2) ◽  
pp. 119-125 ◽  
Author(s):  
Masahiro Hosono ◽  
Tohru Hiruma ◽  
Kiyoshi Watanabe ◽  
Yutaka Hayashi ◽  
Haruo Ohnishi ◽  
...  

2020 ◽  
Vol 34 (S1) ◽  
pp. 1-1
Author(s):  
Pamela Nithzi Bricher Choque ◽  
Maria Helena Mattos Porter ◽  
Luiz Fernando Pereira ◽  
Humberto Dellè ◽  
Maria Claudia Irigoyen ◽  
...  

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