BACKGROUND: One of prominent cardiovascular effects of imipramine is postural hypotension. The present study was to verify whether imipramine has a central hypotensive action and futher to investigate its mechanism of action. METHODS: Rats(male, Sprague-Dawley) weighing 250-300g were anesthetized with pentobarbital sodium(50mg/kg, ip). Imipramine was administered into the left lateral cerebral ventricle. Mean arterial pressure(MAP) and heart rate(HR) were continuously monitored from the right femoral artery. RESULTS: Intracerebroventricular(icv) imipramine(3micromol/kg) caused decrease in MAP without significant alterations in HR, of which safety dose-range was very narrow. 1micromol/kg did not affect MAP and 10micromol/kg caused deaths of animals within 10min. Intravenous infusion of the same dose(3micromol/kg) of imipramine caused only a transient hypotension within 5min. Hexamethonium-treated(1mg/kg/min) rats did not respond to icv imipramine. Regitine pretreatment(2mg/kg, iv) prevented the hypotensive response to icv imipramine. Yohimbine pretreatment(500microg/kg, icv) not only blocked the hypotensive effect, but it caused a transient pressor response to icv imipramine. CONCLUSIONS: These results indicate that imipramine has a separate hypotensive effect which is mediated through central alpha2-adrenoceptors.
Animals ; Blood Pressure ; Cerebral Ventricles ; Femoral Artery ; Heart ; Hypotension ; Hypotension, Orthostatic ; Imipramine* ; Infusions, Intravenous ; Pentobarbital ; Phentolamine ; Rats* ; Yohimbine

BACKGROUND: Prostaglandin system is known to participate in manifestation of the renin-angiotensin system. However, role of prostaglandins on the renin-angiotensin system in development of hypertension is not well established. This study was to examine whether the role of prostaglandins is altered in experimental hypertension. METHODS: Two-kidney, one-clip(2KIC) renal hypertension was made by clipping the left renal artery with a silver clip(internal gap of 0.2mm) and deoxycorticosterone acetate (DOCA)-salt hypertension by subcutaneous implantation of DOCA(200mg/kg) strip plus saline(1%) drinking. They were used 3 weeks later. Age-matched normal rats served as a control. Femoral artery was cannulated and arterial blood pressure and heart rate were monitored continuously. RESULTS: 1) In normotensive rats, saralasin infusion(20 microg/kg/min, IV) caused a decrease in mean arterial pressure without significant alterations in heart rate. Indomethacin-pretreatment(10mg/kg, IP) abolished the depressor response to saralasin. 2) The depressor response to saralasin was more marked in renal hypertensive rats than in normotensive rats. The magnitude of maximum decrease in blood pressure, however, was comparable between the hypertensive and normotensive rats. Indomethacin-pretreatment did not affect the depressor response to saralasin in renal hypertensive rats. 3) In DOCA-salt hypertensive rats, saralasin infusion rather caused an increase in mean arterial pressure without significant alterations in heart rate. The pressor response to saralasin was not affected by indomethacin-pretreatment. CONCLUSION: These results indicate that prostaglandin system may modify renin-angiotensin system in normotensive rats. It is suggested that mechanisms other than prostaglandin system participate in the full-blown manifestation of renin-angiotensin system in 2KIC renal hypertensive rats.
Animals ; Arterial Pressure ; Blood Pressure ; Desoxycorticosterone ; Drinking ; Femoral Artery ; Heart Rate ; Hypertension ; Hypertension, Renal ; Prostaglandins I ; Prostaglandins* ; Rats* ; Renal Artery ; Renin-Angiotensin System* ; Saralasin ; Silver

Reactive human mesothelial cells were examined by immunocytochemical stain with intermediate fiiaments (cytokeratin [CK1, CK7, CK8, CK18, CD19], vimentin, desmin, actin), epithelial membrane antigen, carcinoembryonic antigen (CEA), MHC class II antigen (HLA-DR), LeuM-1 (CD15), alpha1-antitrypsin(ACT), alpha1-antichymotrypsin(ACMT), CD68(KP-1) and FcyRIII(CD16). The mesothelial cells were isolated from patients with liver cirrhosis and pleural effusion, and short-term cultured in RPMI 1640 media containing 10% heat inactivated fetal calf serum and 1% identical supernatant fluid of the patients transudates. The results obtained are as follows. 1. The cultured-reactive mesothelial cells were positive for the protein of cytoskeleton such as cytokeratin and vimentin, but negative for desmin and actin. The resting mesothelial cells showed positive reactions for cytokeratin, but negative for vimentin, desmin and actin. 2. The primary antibodies to the cytokeratin were strongly reactive for CK1, CK8 and CK18 but negative r CK7 and CK19 in both reactive and resting mesothelial cells. 3. Resting mesothelial cells showed negative reactions for CEA, but strong positive reactions in cultured-reactive mesothelial cells. 4. The markers for the monocytes/histiocytes(CD11b, CD14, CD16, CD68, lysozyme and alpha1-antitrypsin and alpha1-antichymotrypsin) were nonreactive in resting mesothelial cells, but lysozyme and alpha1-antitrypsin were weakly reactive in reactive and proliferative mesothelial cells. 5. MHC Class II molecule(HLA-DR antigen) was negative in both resting and reactive mesothelial cells. These results suggest that the short-term cultured, reactive mesothellal cells show a newly aberrant expression of the vimentin and carcino-embryonic antigen. The reason of the aberrant expression of the intermediate filament and oncofetal antigen in reactive and proliferative mesothellal cells should be further evaluated.
Actins ; Antibodies ; Carcinoembryonic Antigen ; Cytoskeleton ; Desmin ; Exudates and Transudates ; Follow-Up Studies* ; Histocompatibility Antigens Class II ; Hot Temperature ; Humans ; Hydronephrosis* ; Intermediate Filaments ; Keratins ; Liver Cirrhosis ; Mucin-1 ; Muramidase ; Pleural Effusion ; Salivary Glands ; Vimentin

BACKGROUND: Aside from its well known peripheral antihypertensive effects, calcium also lowers blood pressure, when administered into the cerebral ventricle. The present study was aimed to determine whether the central depressor response to calcium is mediated by a stimulation of endogenous L-arginine-nitric oxide (NO) pathway. METHODA: Mean arterial pressure (MAP) and heart rate (HR) were continuously recorded from the femoral artery in anesthetized rats. Administration of calcium was performed into the right lateral cerebral ventricle. The effects of N G-nitro-L-arginine methyl ester (L-NAME) on the cardiovascular response to calcium were examined. RESULTS: Intracerebroventricular (ICV) injection of calcium consistently produced a decrease in MAP and HR. The depressor and bradycardiac responses to calcium showed a dose-dependent fashion. Pretreatment with a calcium channel blocker, diltiazem (1 micromol, ICV), attenuated cardiovascular responses to calcium. ICV infusion (1 microl/min) of L-NAME (200 microgram/kg and 20 microgram/kg/min for 60 min) increased MAP without significant changes in HR. Chronic ingestion of L-NAME (5 mg/100 ml in drinking water, 4 weeks) also increased the systolic blood pressure as compared with control. The depressor effect of ICV calcium was significantly diminished in acute or chronic L-NAME treated rats. CONCLUSION: These findings suggest that the central depressor response to calcium, at least in part, is NO-dependent.
Animals ; Arterial Pressure ; Blood Pressure ; Calcium Channels ; Calcium* ; Cerebral Ventricles ; Diltiazem ; Drinking Water ; Eating ; Femoral Artery ; Heart Rate ; NG-Nitroarginine Methyl Ester ; Nitric Oxide* ; Rats

BACKGROUND: An increase of the extracellular K+concentrations up to about 8 mM in the isolated vessels causes relaxation in pre-contracted state. In order to elucidate the mechanisms of K+induced relaxation and compare with that of 2-kidney, 1 clip (2K1C) renal hypertensive rats, we recorded aortic vascular tension using an organ bath study. METHOD: 2K1C hypertension was made by clipping the left renal artery and age-matched control rats received a sham treatment. Thoracic aortic rings were mounted in tissue baths for measurement of isometric contractile force. RESULTS: Exposure to K+(from 2 to 8 mM) relaxed a phenylephrine (2 x 10-6 M)-induced contraction in K+free Krebs-Ringer solution, dose-dependently. Ouabain (10-5 M) enhanced the K+induced relaxation in above 2 mM K+ The K+induced relaxation was still induced in endothelium-denuded condition. Incubation with the K+channel blockers such as tetraethylammonium (TEA, 1 mM), glibenclamide (10-5 M), 4-aminopyridine (3 mM), barium (5 mM) and cesium (2 mM) did not affect on the K+induced relaxation. In renal hypertensive rats, the K+induced relaxation was markedly suppressed and ouabain enhanced it. CONCLUSIONS: These results suggest that the K+induced relaxation in aorta be mediated by Na-pump independent mechanisms, and the decrease of the K+induced relaxation in the renal hypertensive rats may be a possible mechanism of hypertension.
4-Aminopyridine ; Animals ; Aorta ; Barium ; Baths ; Cesium ; Glyburide ; Hypertension ; Muscle, Smooth* ; Ouabain ; Phenylephrine ; Placebos ; Rats* ; Relaxation ; Renal Artery ; Tetraethylammonium ; Vasodilation*

BACKGROUND: An increase of the extracellular K+concentrations up to about 8 mM in the isolated vessels causes relaxation in pre-contracted state. In order to elucidate the mechanisms of K+induced relaxation and compare with that of 2-kidney, 1 clip (2K1C) renal hypertensive rats, we recorded aortic vascular tension using an organ bath study. METHOD: 2K1C hypertension was made by clipping the left renal artery and age-matched control rats received a sham treatment. Thoracic aortic rings were mounted in tissue baths for measurement of isometric contractile force. RESULTS: Exposure to K+(from 2 to 8 mM) relaxed a phenylephrine (2 x 10-6 M)-induced contraction in K+free Krebs-Ringer solution, dose-dependently. Ouabain (10-5 M) enhanced the K+induced relaxation in above 2 mM K+ The K+induced relaxation was still induced in endothelium-denuded condition. Incubation with the K+channel blockers such as tetraethylammonium (TEA, 1 mM), glibenclamide (10-5 M), 4-aminopyridine (3 mM), barium (5 mM) and cesium (2 mM) did not affect on the K+induced relaxation. In renal hypertensive rats, the K+induced relaxation was markedly suppressed and ouabain enhanced it. CONCLUSIONS: These results suggest that the K+induced relaxation in aorta be mediated by Na-pump independent mechanisms, and the decrease of the K+induced relaxation in the renal hypertensive rats may be a possible mechanism of hypertension.
4-Aminopyridine ; Animals ; Aorta ; Barium ; Baths ; Cesium ; Glyburide ; Hypertension ; Muscle, Smooth* ; Ouabain ; Phenylephrine ; Placebos ; Rats* ; Relaxation ; Renal Artery ; Tetraethylammonium ; Vasodilation*

PURPOSE: Locoregional recurrence of breast cancer after surgery has been regarded as a harbinger of distant metastases. The present study was undertaken to determine survival following surgical excision of isolated locoregional recurrence and to analyze prognostic factors for their impact on survival after locoregional recurrence. Also, this study may provide information on the group that benefits from surgical management. METHODS: From March 1993 to December 1998, of 43 patients with isolated locoregional recurrence after breast cancer surgery, 26 patients were treated with surgical excision with or without irradiation. Survival was retrospectively analyzed according to prognostic factors. RESULTS: The median follow-up was 15 months. The 3-year disease-free survival rates were 50% for locoregional recurrences treated with surgical resection and 6% for patients treated without surgery (p=0.04), and the overall survival rates were 63% and 14%, respectively (p=0.07). Univariative analysis demonstrated that the initial axillary node status and the disease-free interval were significant prognostic factors for overall survival (p=0.04 and p=0.06, respectively). The disease-free interval from surgery to recurrence was also a significant prognostic factor for disease-free survival (p=0.03). CONCLUSION: These results suggest that patients suffering from isolated locoregional recurrence of breast cancer after a long disease-free interval and an initial node negative status may survive for long periods of time with aggressive surgical treatment.
Breast Neoplasms* ; Breast* ; Disease-Free Survival ; Follow-Up Studies ; Humans ; Neoplasm Metastasis ; Recurrence* ; Retrospective Studies ; Survival Rate

Bradykinin has been known to elicit a pressor effect when administered centrally, and a depressor effect when administered peripherally. The present study was aimed at investigating whether the blood pressure response to bradykinin is dependent on the endogenous generation of nitric oxide (NO). Effects of NG-nitro-L-arginine methyl ester (L-NAME) on the pressor and depressor responses to intracerebroventricularly and intravenously injected bradykinin (5nmol/rat), respectively, were examined in anesthetized rats. Neither the pressor response nor the depressor response was affected by acute parenteral treatment with L-NAME. The pressor and depressor effects of bradykinin were also noted in rats chronically supplemented with L-NAME in drinking water for 4 weeks. Bradykinin caused a relaxation of the isolated thoracic aorta in vitro, which was not affected in the presence of L-NAME. However, bradykinin failed to cause a relaxation of the aorta isolated from rats chronically treated with L-NAME. These findings suggest that endogenous generation of NO may not completely account for the blood pressure responses to bradykinin in rats.
Animals ; Aorta ; Aorta, Thoracic ; Blood Pressure* ; Bradykinin* ; Drinking Water ; NG-Nitroarginine Methyl Ester ; Nitric Oxide* ; Rats* ; Relaxation

BACKGROUND: Calcium plays a key role in vascular contraction and regulates receptor sensitivity to certain neurotransmitters. Calcium channel blockers are useful in the treatment of both clinical and experimental hypertension. The present study was designed to examine whether there is an alteration of the activity of calcium channels in association with the development of hypertension. METHODS: Deoxycorticosterone acetate(DOCA)-salt hypertension was made by subcutaneous implantation of DOCA(200mg/kg)strip plus saline drinking(1%) and 2-kidney, 1 clip(2KIC)hypertension by clipping the left renal artery with a silver clip(internal gap of 0.2mm). They were used 4 weeks later. Age-matched normal rats served as a control. Mean arterial pressure(MAP) and heart rate(HR) were continuously recorded from the right femoral artery. The drugs were administered intravenously. RESULTS: Vehicle alone was without effect on MAP or HR. In normotensive rats, nifedipine infusion(5 and 10ug/kg/min)caused a dose-dependent decrease in MAP without significant changes in HR, while Bay k 8644(Bay K, 5 and 10 ug/kg/min) increased MAP transiently. Both the depressor response to nifedipine and the pressor response to Bay k were more marked in DOCA-salt hypetensive rats than in normotensive rats. The maximal changes in MAP indced by nifedipine(5 and 50 ug/kg) or Bay K(5 and 50 ug/kg) were also enhanced in 2KIC hypertensive rats as compared with control rats. CONCLUSION: These results indicate that calcium channel inhibitors and activators can affect on the regulation of blood pressure in an opposite fashion. It is also suggested that the activity of calcium channels might be altered in the developement of experimental hypertension.
3-Pyridinecarboxylic acid, 1,4-dihydro-2,6-dimethyl-5-nitro-4-(2-(trifluoromethyl)phenyl)-, Methyl ester* ; Animals ; Bays* ; Blood Pressure ; Calcium ; Calcium Channel Blockers ; Calcium Channels ; Desoxycorticosterone ; Femoral Artery ; Heart ; Hypertension ; Neurotransmitter Agents ; Nifedipine* ; Rats* ; Renal Artery ; Silver

Although many studies show that thromboxane A2 (TXA2) has the action of gastrointestinal (GI) motility using GI muscle cells and tissue, there are no reports on the effects of TXA2 on interstitial cells of Cajal (ICC) that function as pacemaker cells in GI tract. So, we studied the modulation of pacemaker activities by TXA2 in ICC with whole cell patch-clamp technique. Externally applied TXA2 (5 micrometer) produced membrane depolarization in current-clamp mode and increased tonic inward pacemaker currents in voltage-clamp mode. The tonic inward currents by TXA2 were inhibited by intracellular application of GDP-beta-S. The pretreatment of ICC with Ca2+ free solution and thapsigargin, a Ca2+-ATPase inhibitor in endoplasmic reticulum, abolished the generation of pacemaker currents and suppressed the TXA2-induced tonic inward currents. However, chelerythrine or calphostin C, protein kinase C inhibitors, did not block the TXA2-induced effects on pacemaker currents. These results suggest that TXA2 can regulate intestinal motility through the modulation of ICC pacemaker activities. This modulation of pacemaker activities by TXA2 may occur by the activation of G protein and PKC independent pathway via extra and intracellular Ca2+ modulation.
Animals ; Benzophenanthridines ; Endoplasmic Reticulum ; Gastrointestinal Motility ; Gastrointestinal Tract ; GTP-Binding Proteins ; Guanosine Diphosphate ; Interstitial Cells of Cajal ; Intestines ; Membranes ; Mice ; Muscle Cells ; Naphthalenes ; Patch-Clamp Techniques ; Protein Kinase C ; Thapsigargin ; Thionucleotides ; Thromboxane A2