• The Korean Journal of Physiology and Pharmacology
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• v.5 no.3
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• pp.253-258
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• 2001

The present study was aimed to examine whether the expression of renin is associated with that of cyclooxygenase-2 (COX-2) in the kidney. Male Sprague-Dawley rats were made two-kidney, one clip (2K1C) or deoxycorticosterone acetate (DOCA)-salt hypertensive, to stimulate or to inhibit the endogenous renin-angiotensin system, respectively. The expression of renin and COX-2 mRNA was determined in the cortex of the kidney by reverse transcription-polymerase chain reaction. 2K1C hypertensive rats showed an increased expression of renin as well as of COX-2 in the clipped kidney. The expression of renin was decreased in parallel with that of COX-2 in the contralateral non-clipped kidney. Removal of the renal arterial clip reversed the expression of both genes, along with the blood pressure, to the control level. On the other hand, DOCA-salt hypertension was associated with parallel decreases of renin and COX-2 expression. These results indicate that renin and COX-2 genes are coordinately expressed in the kidney.

• The Korean Journal of Physiology
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• v.23 no.1
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• pp.43-49
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• 1989

Effects of atrial natriuretic peptide (ANP) on the development of hypertension in 2-kidney, 1-clip (2-K, 1-C) rats were examined. In one group of rats, ANP infusion (500 ng/hr, iv) started immediately after clipping the renal artery. Another group of rats with one kidney-clipped was without ANP infusion and served as a control. Blood pressure was measured on days 4, 7, and 10 following clipping the renal artery. Upon the last blood pressure measurement finished, blood sample was collected by decapitation to measure plasma renin activity (PRA), and both kidneys were taken to weigh and to measure renin content. The ANP-infused group showed an attenuation of increases in blood pressure compared to the non-infused control group. PRA was lower in the ANP-infused group than in the non-infused group. Cortical renal renin content (RRC) of the clipped kidneys was not different between ANP-infused and non-infused groups. The clipped kidneys showed a higher RRC and weighed less than the non-clipped contralateral kidneys within each group. In contrast, sham-clipped rats did not show significant changes in any of the parameters examined regardless of whether ANP was infused or not. These results demonstrate that chronic ANP infusion does not prevent but does attenuate the development of hypertension in 2-K, 1-C rats. It is suggested that ANP plays a role in the long-term regulation of blood pressure, at least in part, by antagonizing the renin-angiotensin-system.

• The Korean Journal of Physiology and Pharmacology
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• v.2 no.4
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• pp.455-460
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• 1998

The present study was aimed at investigating whether the development of hypertension is related with an altered expression of nitric oxide synthases (NOS) in the kidney. By Western blot analysis, the expression of bNOS and ecNOS isoforms was determined in the kidney of deoxycorticosterone acetate (DOCA)-salt and two-kidney, one clip (2K1C) rats. In DOCA-salt hypertension, the expression of both bNOS and ecNOS was decreased, along with tissue contents of nitrites. In 2K1C hypertension, the nitrite content of the clipped kidney was decreased along with ecNOS levels, whereas neither the nitrite content nor the expression of NOS isoforms was significantly altered in the contralateral non-clipped kidney. These results suggest that the development of hypertension is associated with an altered renal expression of NOS and nitric oxide generation in DOCA-salt and 2K1C rats.

• The Korean Journal of Physiology and Pharmacology
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• v.4 no.2
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• pp.143-147
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• 2000

The present study was aimed at investigating whether there are changes in the expression of nitric oxide synthase (NOS) in relation with the unclipping-induced fall of blood pressure in two-kidney, one clip (2K1C) hypertension. Male Sprague-Dawley rats were made 2K1C hypertensive by clipping the left renal artery for four weeks. Sham-clipped rats served as control. The expression of endothelial constitutive (ec) NOS proteins and tissue levels of NO metabolites were determined in the kidney. Systolic blood pressure was significantly increased in clipped rats compared with that in the control. The development of hypertension was associated with decreases in the expression of ecNOS proteins and tissue levels of NO metabolites in the clipped kidney. The blood pressure at twenty-four hours after removal of the renal arterial clip fell to the control level. Accordingly, in the unclipped kidney, the expression of ecNOS proteins and tissue contents of NO metabolites were increased to the control level. The contralateral kidney was not affected by the development or reversal of hypertension. It is suggested that an enhanced expression of ecNOS in the unclipped kidney is an important component in the reversal of renovascular hypertension.

• The Korean Journal of Physiology
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• v.30 no.1
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• pp.33-41
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• 1996

The present study was aimed to investigate the role of endothelium-derived nitric oxide (NO) in the control of renin release and to examine if NO is implicated in the development of two-kidney, one clip (2K1C) hypertension. Male Sprague-Dawley rats $(150{\sim}200\; g)$ were constricted at the left renal artery. They were then supplemented with $N^{G}-nitro-L-arginine\;methyl\;ester\;(L-NAME,\; 5mg/100\;mL)$ or with L-arginine hydrochloride (400 mg/100 mL) in the drinking water. The control group was supplied with normal tap water. The sham-clipped rats were operated as in 2K1C rats except for that no clip was made. The kidneys were taken to examine in vitro release of renin at days 7 and 14 following clipping the renal artery. Northern blot analysis was also done to assess the expression of renin gene in the kidney. In sham-clipped rats, L-NAME caused a sustained increase of the blood pressure, whereas L-arginine was without effect. Neither L-NAME nor L-arginine-supplementation significantly affected the development of hypertension in 2K1C rats. Plasma renin concentration (PRC) measured on day 28 did not significantly differ among the L-NAME, L-arginine and control groups either in 2K1C or in sham-clipped rats. Renin contents (RRC) in the clipped kidney were increased, while those in the contralateral kidney were decreased. The release of renin in vitro from cortical slices was also enhanced in the clipped kidney, whereas it was attenuated in the contralateral. Comparing the RRC and in vitro release, the latter was more rapidly decreased than the former in the contralateral kidney. The renin mRNA levels in the contralateral kidney were almost at their nadir at days 7 and 14 in 2K1C rats. It is suggested that NO does not affect the development of 2K1C hypertension in which the renin-angiotensin system has been activated. The data also confirm that RRC and renin gene expression are increased in the clipped kidney and suppressed in the contralateral kidney in 2K1C rats.

• The Korean Journal of Physiology and Pharmacology
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• v.8 no.3
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• pp.147-151
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• 2004

The present study was undertaken to determine the regulation of heat shock proteins (HSP) in the kidney in hypertension. Two-kidney, one clip (2K1C) or deoxycorticosterone acetate (DOCA)-salt hypertension was induced in male Sprague-Dawley rats. At weeks 1 and 4 after inducing the hypertension, the expression of HSP70, HSP32 and HSP25 was determined in the kidney by Western blot analysis. In 2K1C hypertension, the expression of HSP70, HSP32 and HSP25 was increased in the clipped kidney at both weeks 1 and 4. However, in the contralateral kidney, their expression was not significantly altered at week 1, but increased at week 4. In DOCA-salt hypertension, the expression of HSP remained unaltered in the remnant kidney at week 1, but significantly increased at week 4. These results indicate that HSP are differentially regulated in the kidney according to the duration and the model of hypertension.

• The Korean Journal of Physiology
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• v.26 no.1
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• pp.69-74
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• 1992

Central cardiovascular effects of bradykinin were examined in anesthetized normotensive (NTR) and 2-kidney, 1 clip Goldblatt hypertensive rats (GHR). Bradykinin ($0.5{\sim}10nmol$) was administered into the right lateral cerebral ventricle, while blood pressure and heart rate (HR) were continuously monitored. In both NTR and GHR, intracerebroventricular bradykinin produced a dose dependent increase in mean arterial pressure (MAP) without significant changes in HR. GHR were more sensitive in the pressor response than NTR. The pressor response to bradykinin was attenuated by treatment with hexamethonium (2.5mg/kg/min, IV) or phentolamine (2mg/kg, IV) in both NTR and GHR. Reserpine treatment (2mg/kg/day, intramuscularly,2 days) did not affect the central pressor effect of bradykinin in NTR but it attenuated the pressor effect in GHR. Pretreatment with indomethacin (10mg/kg, intraperitoneally) or saralasin ($20{\mu}g$/kg/min, IV) was without effects on the pressor response to bradykinin. These results indicate that the central pressor effect of bradykinin is, at least in part, due to excitation of the autonomic nervous activity. Mechanisms other than the enhanced sympathetic nervous activity ran. not be ruled out, However. It is also suggested that the sensitivity to bradykinin is increased in the GHR.

• Journal of Acupuncture Research
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• v.24 no.3
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• pp.29-38
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• 2007

Objectives : The purpose of this study was to investigate the effects of $Taegye(KI_3)$ acupuncture and acupuncture with twirling method on the blood pressure, cardiomegalic index, plasma levels of renin and atrial natriuretic peptide in hypertensive RAT induced by two kidney one clip (2KIC). Methods : This study was conducted on one control group and four experimental groups. Control group that had no treatment, Tail group that took tail acupuncture, K-0 group that took $KI_3$ acupuncture, K-6 group that took $KI_3$ acupuncture with 6 turns of twirling method, K-9 group that took $KI_3$ acupuncture with 9 turns of twirling method. Results : Blood pressure was decreased significantly after $KI_3$ acupuncture. Cardiomegalic index decreased significantly after $KI_3$ acupuncture. Plasma levels of renin was decreased significantly after $KI_3$ acupuncture and acupuncture with 9 turns of twirling method Ⅳ. Plasma levels of atrial natriuretic peptide was increased significantly after $KI_3$ acupuncture. Conclusions : These results suggest that blood pressure was decreased significantly after $KI_3$ acupuncture in hypertensive RAT induced by two kidney one clip (2K1C).

• The Korean Journal of Physiology
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• v.20 no.1
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• pp.89-102
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• 1986

It has long been suggested that the change of renin-angiotensin system is responsible for the increased arterial blood pressure in the experimental hypertension. But the exact nature of the cause and maintenance of early and late Phase of renal hypertension is still controversial. Increased renin-angiotensin system has been suggested. To clarify the altered renin-angiotensin system in the early phase of two kidney one clip Goldblatt hypertension(2K1C GH), experiments were carried out in the rats of 3,7, and 14 days of 2K1C GH rats, sham-operated, and control rats. Responses of the plasma renin activity to the intravenous infusion of L-isoproterenol were dose-dependent. Responses of the plasma renin activity to the intravenous L-isoproterenol in 2K1C GH rats were not different from sham-operated control rats. Hypotensive responses of the 2K1C GH rats were not different from sham-operated rats. Suppression by intravenous infusion of angiotensin II of plasma renin activity showed a dose-dependent manner. Suppression by angiotensin ll of plasma renin activity was attenuated or abolished in the early phase of 2K1C GH rats. Intravenous infusion of arginine vasopressin(AVP) showed a dose-dependent suppression of plasma renin activity, Attenuated responses by AVP of plasma renin activity were noticed in the early phase of 2K1C GH rats. These results suggest that the altered renin-angiotensin system in the early phase of the two kidney one clip Goldblatt hypertension may be caused by failure of the short loop negative feedback control mechanism.

• The Korean Journal of Physiology and Pharmacology
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• v.4 no.5
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• pp.385-391
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• 2000

Using the patch-clamp technique, we investigated the alteration of 4-aminopyridine(4-AP)-sensitive, voltage-dependent $K^+$ channel (Kv) in the mesenteric arterial smooth muscle cell (MASMC) of renovascular hypertensive model, one-kidney one-clip Goldblatt hypertensive rat (GBH). To isolate $K_V$ current, internal pipette solution contained 5 mM ATP and 10 mM EGTA. Under these condition, MASMC was depolarized by 4-AP, but charybdotoxin did not affect membrane potential. Membrane potential of hypertensive cell $(-40.3{\pm}3.2\;mV)$ was reduced when compared to that of normotensive cell $(-59.5{\pm}2.8\;mV).$ Outward $K^+$ current of hypertensive cell was significantly reduced when compared to normotensive cell. At 60 mV, the outward currents were $19.10{\pm}1.91$ and $14.06{\pm}1.05$ pA/pF in normotensive cell and hypertensive cell respectively. 4-AP-sensitive $K^+$ current was also smaller in hypertensive cell $(4.28{\pm}0.38\;pA/pF)$ than in normotensive cell $(7.65{\pm}0.52\;pA/pF).$ The values of half activation voltage $(V_{1/2})$ and slope factor (k1) as well as the values of half inactivation voltage $(V_{1/2})$ and slope factor (k1) were virtually similar between GBH and NTR. These results suggest that the decrease of 4-AP-sensitive $K^+$ current contributes to a depolarization of membrane potential, which leads to development of vascular tone in GBH.