Plasma concentrations of platelet-specific proteins in different stages of essential hypertension: interactions between platelet aggregation, blood lipids and age

Plasma beta-thromboglobulin (beta TG) and platelet factor 4 (PF4) were significantly higher in a group of 116 hypertensive men than in a normotensive group of 142 men. They increased with the stage of hypertension but the level did not correlate with the age of the subjects. Platelet aggregation was similar in the two groups and positively correlated with the age of the subjects in the normotensive group but not in the hypertensive group. A strong positive correlation was observed between the levels of plasma beta TG and PF4 and between platelet aggregation to ADP and that to epinephrine in both the hypertensive and normotensive groups. However, there was no correlation between the level of plasma beta TG or PF4 and platelet aggregation. Plasma antithrombin III was lower in the hypertensive group than in the normotensive group. These studies suggest that plasma levels of beta TG and PF4 are closely related to the stage of hypertension and are better indicators than aggregation of in vivo platelet activation in hypertensive subjects. Enhanced platelet activation may be involved in the acceleration of hypertensive arteriovascular damage and atherosclerosis.

Termination of ventricular tachycardia by an implantable atrial pacemaker and external pacemaker activator

An atrial pacemaker was implanted in a patient who had dilated cardiomyopathy, sinus node dysfunction, and drug-resistant ventricular tachycardia (VT). VT episodes were terminated by atrial overdrive pacing using an implanted pacemaker and a newly developed hand-held external programmer/transmitter. Although successful cases of termination of intractable VT by ventricular pacing have recently been reported, the ventricular method might increase the risk of accelerating VT. Atrial overdrive pacing is a safer method since it minimizes the possibility of tachycardia acceleration and, combined with antiarrhythmic drugs, it appeared to be a unique and useful approach for the treatment of drug-resistant VT.

[Left ventricular peak filling velocity and its relevant factors in hypertrophic hearts]

To evaluate the relevant factors of left ventricular peak filling velocity, M-mode echocardiograms showing the left ventricular cavity were recorded and digitized for 81 patients with hypertrophic hearts (HTH) due to hypertensive heart disease (HHD, n = 30), hypertrophic cardiomyopathy (HCM, n = 25), aortic valve stenosis (AS, n = 9), and HHD and HCM with congestive heart failure (HHD and HCM with CHF, n = 17). Peak rates of increase or decrease in dimension (Vf and Ve, respectively) and peak values of instantaneous circumferential fiber lengthening and shortening velocities (Vf/D and Ve/D, respectively) were determined by computer analysis of left ventricular internal dimensions. Systolic excursion (SE), percent fractional shortening (%FS), mean circumferential fiber shortening velocity (mVcf), thickness of the interventricular septum and posterior wall at end-diastole and the sum of them (WThivs, WThpw, and WThivs + pw, respectively) were also calculated. Their variables were compared with those of normal subjects (n = 24). The results obtained were as follows: Systolic functions in HTH without CHF were similar to those of the normal subjects, but Vf and Vf/D were significantly decreased. Differences in Vf and Vf/D between various HTH without CHF were not significant. In AS and HTH with CHF, Vf and Vf/D were significantly decreased together with systolic function. Vf correlated significantly with WThivs + pw, SE, Ve, and WThivs, and Vf/D with %FS, SE, Ve/D, and Ve.(ABSTRACT TRUNCATED AT 250 WORDS)

[Hypertrophic cardiomyopathy with progressive left ventricular hypertrophy: a case report]

A 64-year-old man was hospitalized in March 1983 for recurrent episodes of dyspnea and palpitation despite medical treatment. At 48 years of age (1967), hypertension was diagnosed, but well controlled by propranolol. At the age of 59 years (1979), his first episode of dyspnea and palpitation was noted, with electrocardiographic (ECG) evidence of left ventricular hypertrophy (LVH), and abnormal Q waves in leads III and a VF. The echocardiogram, however, showed mild LVH with neither asymmetric septal hypertrophy (ASH) nor systolic anterior movement (SAM). On admission (1983), his blood pressure was 130/70 mmHg, and a grade III systolic murmur was heard along the left sternal border and over the apex. On ECG, the left precordial voltage (Sv1 + Rv5) was diminished and the depth of the Q wave in lead III increased compared with that of 1978. On echocardiography, we observed prominent septal hypertrophy (IVST: 20 mm) with ASH (IVST/PWT = 2.0), SAM, an enlarged left atrium, and a diminished left ventricular (LV) cavity. Left ventricular catheterization showed a pressure gradient of 90 mmHg between the LV apex and outflow tract and histological examination of the bi-ventricular endomyocardial biopsy material showed markedly hypertrophied and mildly disarranged myocardial fibers with bizarre nuclei. We considered that this was an interesting case in which ASH and SAM developed in the progression of LVH during the follow-up period.

Abnormal relationship between dietary sodium intake and red cell sodium transport in salt-sensitive patients with essential hypertension

The effects of high sodium intake on erythrocyte 22Na efflux rate constants were studied in 25 patients with essential hypertension and 9 normal subjects. With changes in sodium intake from 100 mEq to 300 mEq/day, both total and ouabain sensitive 22Na efflux rate constants decreased significantly (p less than 0.001) in "salt-sensitive" patients (-0.031 +/- 0.005 and -0.035 +/- 0.006 /hr, respectively), but these responses were variable in "nonsalt-sensitive" patients and in normal subjects. The "salt-sensitive" patients showed a significant increase in their body weight, while intraerythrocyte sodium contents remained unchanged in the both groups. These results suggest that the abnormal change in membrane Na-K-ATPase activity may, at least in part, be involved in the mechanism of sodium susceptibility in patients with essential hypertension.

Changes of left ventricular pressure-diameter-velocity relations by alterations of heart rate in conscious dogs

Changes of left ventricular (LV) pressure-diameter-velocity relations by alterations in heart rate (HR) were investigated in 6 conscious dogs, instrumented with a pair of ultrasonic crystal probe, a micromanometer in LV and pacing electrodes on the left atrium. By atrial pacing the following four stages of HR were produced: stage (S)-I 112, S-II 134, S-III 158 and S-IV 179 bpm (mean HR). These alterations in HR were repeated before and during acute pressure loadings by methoxamine infusion. LV pressure-diameter and pressure-velocity relations were evaluated by the slope value of LV peak systolic pressure (LVSP)-end-systolic diameter, E (D) max, and by the ratio of changes in mV cf (mean velocity circumferential fiber shortening) and LVSP before and during pressure loading, delta mVcf/delta LVSP, respectively. The average of E(D) max at each stage of HR was 9.45, 12.63, 12.59, 11.22 mmHg/mm, and delta mVcf/delta LVSP was -0.009, -0.006, -0.007, -0.009 circ./sec.mmHg, respectively. E(D) max increased more at S-II and S-III than at S-I, and reversely, E(D) max decreased more at S-IV than at S-II. Similarly, delta mVcf/delta LVSP increased more at S-II than at S-I and decreased more at S-IV than at S-II, while delta LVSP and delta EDD (end-diastolic diameter) were not different between stages. These changes in E(D) max and delta mVcf/delta LVSP presented the mountainous pattern effected by alterations in HR, whose changes were almost similar to that of LV peak positive dp/dt and mVcf before pressure loading. Thus, E(D) max is augmented by an increase in HR, which suggests the Bowditch-effect. Reversely, a decrease in E(D) max at a higher rate indicates a depressed inotropic state. E(D) max is dependent on HR and is a sensitive indicator of the contractility of LV.

Reconsideration of heart rate-cardiac output relationships and resting cardiac function in patients with brady-arrhythmias

Different types of heart rate (HR)-cardiac output (COP) relationships were compared with their clinical features and hemodynamic findings in 56 patients with brady-arrhythmias (BA). HR was raised by increments of 10 beats per minute (bpm) at 3 min intervals, from spontaneous rates to 100 or 110 bpm by right ventricular pacing. Cardiac and left ventricular (LV) functions at BA were evaluated by intra-cardiac pressures, COP measured by the thermo-dilution method and echocardiographic data. HR-COP relationships were divided into the following 3 types: 24 patients of flat (F), 18 of peaked (P) and 14 of increased (I) type. There were more patients with complete atrio-ventricular block, particularly His-ventricular block, and cardiomyopathic patients with the "P" type than with the other types. Cardiac index, stroke index, stroke work index and systemic vascular resistance were greater in "I", but these differences were not significant. LV peak systolic pressure (LVSP) and end-diastolic pressure (EDP) in "I" increased more than in "F". EDP, LV end-diastolic and end-systolic dimension (ESD) in "P" increased more than in "F". Systolic excursion and LVSP/ESD ratio in "I" increased more than in the other types. Heart failure prior to implantation of pacemaker (PM) and post-PM occurred more frequently in "P". "F" and "I" patients showed comparatively good clinical courses after PM. Thus, cardiac and LV function during BA are maintained in "F" and are impaired in "P", as reported previously. On the other hand, cardiac functions are maintained in "I" as they are in "F", mainly due to contributions of the Frank-Starling mechanism and partly due to maintenance or slight augmentation of contractility.

Abnormal red cell sodium content and efflux in Japanese patients with essential hypertension

Net sodium (Na) efflux and potassium (K) influx were determined in Na-loaded/K-depleted erythrocytes derived from 37 patients with essential hypertension and 25 age-matched normotensive subjects with no family history of hypertension, together with the measurement of basal red cell sodium and potassium contents. Intraerythrocyte sodium content was significantly higher in the essential hypertensives than in the normotensives (10.9 +/- 1.4 vs 10.0 +/- 1.2 mmol/L X cells, mean +/- SD, p less than 0.02), but potassium content was nearly equal between the two groups. Net Na efflux in the hypertensives was significantly reduced compared with that in the normotensives (4.57 +/- 0.70 vs 5.18 +/- 1.02 mmol/L X cells X hr, p less than 0.01), but both net K influx and net Na/K flux ratio were not significantly different between the two groups. Net Na efflux and K influx showed a significant inverse correlation with red cell sodium content (r = -0.64 and r = -0.56, respectively, p less than 0.001). These results suggest that the reduced net Na efflux with the increase of red cell sodium content may be related to the pathogenesis of essential hypertension. However, it is impossible to determine the genetic marker of essential hypertension by using the net Na/K flux ratio of Japanese subjects, although Garay et al. have reported that this index was abnormally low in the case of Europeans.

Casting properties of Ni-Ti shape memory alloy

A Ni-45 wt% Ti (Ni-50 at % Ti) alloy was cast into molds of magnesia and silica investments by use of a dental argon-arc pressure casting machine with a copper crucible . The castings exhibited shape memory properties. The shape recovery process was sharper in the specimens cast in magnesia investment molds than in those cast in silica (phosphate-bonded) investment molds. The latter casting had a hard region of the periphery, suggesting that shape recovery process may be affected by reaction of molten metal with silica. Furthermore, the alloy possessed the adequate mechanical properties for consideration as crown-and-bridge prostheses.

Elevation of cytoplasmic free calcium concentration by stable thromboxane A2 analogue in human platelets

9, 11-Epithio-11, 12-methano-thromboxane A2 (STA2), a stable analogue of thromboxane A2, caused a rapid rise in cytoplasmic free Ca2+ concentration ([Ca2+]i) in human platelets as measured with the fluorescent Ca2+ indicator quin2. Concomitantly, this compound induced phosphorylation of myosin light chain which is catalyzed by Ca2+, calmodulin-dependent protein kinase. These reactions were fast enough to trigger serotonin release. 13-Azaprostanoic acid, a receptor level antagonist of thromboxane A2 inhibited STA2-induced elevation of [Ca2+]i, phosphorylation of myosin light chain and serotonin release. These results provide evidence that STA2 interacts with a thromboxane A2 receptor which leads to elevation of [Ca2+]i.

Toxicological studies on bestatin. IV. Studies on antigenicity, ocular mucosal irritation and mutagenicity

The antigenicity, local irritation and mutagenicity tests of bestatin (NK421) were carried out as special toxicity studies. The antigenicity tests in rabbits and guinea pigs were as follows: active and passive anaphylactic shock tests, Schultz-Dale reaction test, PCA (passive cutaneous anaphylaxis) reaction test, agar gel precipitation test, hemagglutination test of tannic acid-treated erythrocyte and the test according to the appraisal in the U.S.A. The ocular mucosal irritation test in rabbits was performed as a local irritation test. The mutagenicity test was made using S. typhimurium TA100, TA98 strains by means of preincubation method. The results were that NK421 had no antigenicity, irritation on the ocular mucosa and mutagenicity.

[Left ventricular performance during exercise in patients with constant heart rate]

In order to evaluate the response of left ventricular (LV) performance in pacemaker implanted patients (PMI pts) with constant heart rate during exercise, supine bicycle ergometer exercise was performed simultaneously in 21 PMI pts and 4 age-matched normal subjects. PMI pts were classified into two groups; Group I consisted of 16 pts with relatively good physical work capacity (maximal load: male; 80 watt or more, female; 60 watt or more), and Group II consisted of 14 pts with depressed physical work capacity (maximal load: male; 60 watt or less, female; 40 watt or less). During dynamic exercise LV end-diastolic dimension (EDD), stroke excursion (SE), percent fractional shortening (%FS) and posterior wall velocity (PWV) showed a significant increase and LV end-systolic dimension (ESD) showed a significant decrease in Group I in contrast with Group II and normal subjects. Systolic blood pressure (sBP) and sBP/ESD ratio significantly increased in Group I and normal subjects than in Group II. Furthermore, resting cardiac parameters were more impaired in Group II than Group I. Thus, it was suggested that Group I adapted to exercise according to Frank-Starling mechanism (increased EDD) and contractility due to probably increasing circulatory catecholamine (increased PWV and decreased ESD). On the other hand, Group II did not adapt sufficiently to exercise because of the limitation of preload-reserve and contractility-reserve on exercise and also at rest.

Electrophysiological effects of disopyramide phosphate in patients with sinus node dysfunction

The electrophysiological effects of intravenous administration of disopyramide (1.5 mg/kg) were studied in 26 patients with sinus node dysfunction (SND). Disopyramide shortened spontaneous cycle length (SCL) in 12 patients and lengthened it in 4. Maximum sinus node recovery time (max SRT) was prolonged in 9 patients and shortened in 6. Estimated sinoatrial conduction time (SACT) was prolonged in 4 and shortened in 4 out of 10 patients in whom this measurement was possible. However, these changes were not statistically significant. Neither were there any significant changes in PA and AH intervals nor refractory periods of the AV node. HV intervals and refractory periods of the atrium at matched cycle length were significantly lengthened. Atrial echo beats and atrial premature beats disappeared in 7 of 12 patients treated with disopyramide. In all of these 7 patients atrial refractory period were increased. Thus, the disappearance of atrial echo beats and atrial premature beats was thought to be due to a prolonged atrial refractoriness. In 4 patients who had supraventricular arrhythmias without having either marked prolongation of max SRT or episodes of syncope, disopyramide was administered orally for a long term, during which these arrhythmias and symptoms disappeared and sinus rate increased. These results suggest that disopyramide is useful in patients with SND and supraventricular arrhythmias.

Effects of sodium polyacrylate (PANa) on acute esophagitis by gastric juice in rats

Sodium polyacrylate (PANa) is a water-soluble, high-molecular compound, and its aqueous solution shows a very high viscosity and stringiness. In the present study, preventive effects of PANa on three kinds of esophageal lesions induced by gastric juice were examined in comparison with those of aceglutamide aluminum and sodium alginate. The influences of PANa on gastric contents were also studied. The preventive effect of PANa given intraesophageally on esophageal lesions induced by the intraesophageal application of gastric juice was more potent than aceglutamide aluminum and sodium alginate. Oral administration of PANa inhibited the formation of esophageal ulcer by pylorus ligation more markedly than aceglutamide aluminum, whereas sodium alginate had no effect in a high dose of 500 mg/kg. In preventing gastric ulcer which occurred simultaneously with the esophageal ulcer after the pylorus ligation, aceglutamide aluminum was most potent, and PANa was as potent as sodium alginate. Oral administration of PANa showed a more protective effect than aceglutamide aluminum on the esophageal ulceration induced by the simultaneous ligations of the pylorus and limiting ridge, whereas sodium alginate in a high dose of 500 mg/kg had little effect on the ulcer formation. PANa caused only a slight increase in the pH of gastric juice and a slight decrease in pepsin activity. From the results, it may be concluded that PANa showed an antiulcerogenic activity mainly due to its mucosa covering action against gastric juice.

Simultaneous determination of glyceryl trinitrate and its principal metabolites, 1,2- and 1,3-glyceryl dinitrate, in plasma by gas chromatography-negative ion chemical ionization-selected ion monitoring

A specific and sensitive method for the quantitation of glyceryl trinitrate (GTN) and its principal metabolites, 1,2- and 1,3-glyceryl dinitrate (GDN) in dog plasma by capillary gas chromatography-negative ion chemical ionization-selected ion monitoring using dichloromethane as a reagent gas and the corresponding compounds labelled with stable isotopes as internal standards. The quantitation limits of the method for GTN and the GDNs were 0.1 and 1.0 ng/ml in plasma, respectively. When GTN was administered intravenously to four anaesthetized beagle dogs at a dose of 6 micrograms/kg . min for 30 min, the plasma levels of GTN and 1,2- and 1,3-GDN reached a maximum at the end-point of infusion and decreased with bi-exponential decay. The half-lives of the alpha- and beta-phases were 0.50 and 4.95 for GTN, 8.10 and 40.6 for 1,2-GDN and 8.50 and 48.5 for 1,3-GDN, respectively.

[Diastolic murmur in non-obstructive hypertrophic cardiomyopathy]

Diastolic murmur (DM) in patients with non-obstructive hypertrophic cardiomyopathy (non-obst HCM) was studied regarding incidence, phonocardiographic disposition, mechanism, and also clinical characteristics of patients with DM. The results were as follows: 1) DM was recorded in 17 of 115 patients with non-obst HCM (15%), and was classified into three types of a mid-diastolic murmur, presystolic murmur, presystolic murmur and these combination. Mid-diastolic murmur showed low-pitched character mimicking a flow rumble around apical area in most patients. On the other hand, a presystolic murmur was relatively medium-pitched and spindle-shaped over the 4th left sternal border. Additionally, there were 7 patients of mitral opening sound coincided with the "O" point of the apex cardiogram, and 3 patients of an undefined sound or vibration during atrial contraction. 2) Impaired left ventricular (LV) compliance by pressure-volume analysis and decreased diastolic descent rate (DDR) in the mitral echocardiogram observed in patients with DM suggested that mechanism of these DM is mainly attributed to the disturbance of LV filling. Furthermore, mitral regurgitation was detected by LV angiography in a half of patients, indicating that DM might be partially related to increased mitral flow. 3) Clinically, DM was more common in younger patients of familiar occurrence and death, and with impaired physical work capacity. Therefore, auscultatory or phonocardiographic assessment of DM was clinically useful in the evaluation of patients with non-obst HCM.

Haemopathological changes in recurrent deep venous thrombosis of the extremities

We observed 42 (11.7%) patients with multiple or recurrent thrombosis in 358 patients with deep venous thrombosis of the extremities (DVT) and its sequelae. In those patients with recurrent DVT, following characteristics were found in comparison with patients with recurrent DVT, following characteristics were found in comparison with patients who experienced only one episode of DVT. Collagen disease including Behçet disease are often observed as an important predisposing factor. Relatively high incidence in the young generation. Pulmonary embolism occurred about 4 times as frequent as in patients with single episode of DVT. The platelet adhesiveness increased in 7 (38.9%) cases and the hyperaggregability was also frequently found (34.8% by ADP, 26.1% by collagen), though no significant differences was noted from patients with single episode of DVT. Meanwhile, beta-thromboglobulin increased an antithrombin III decreased with a significant difference. DVT with those characteristics should more carefully be managed.

Electrophysiological effects of lidocaine in sick sinus syndrome

Electrophysiological studies were performed to see the effects of lidocaine on the conduction system, particularly sinus node and atrium in 40 patients of SSS, using HBE recordings, rapid atrial pacing and atrial extrastimulus technique. Sinus cycle length, PA (P'A), AH, HV intervals, calculated SACT, and refractory periods of atrium, AV node and His-Purkinje system did not change after lidocaine. Only maximum CSRT was significantly increased with lidocaine. These results were not affected by pretreatment of atropine. In conclusion, the combining rapid atrial pacing with lidocaine may be useful to manifest the masked sinus node abnormalities. It was suggested that lidocaine directly depressed sinus node automaticity in SSS patients, without affecting perinodal tissue. Therefore, lidocaine should be used with caution in patients with known or suspected SSS.

[General pharmacological studies on pepleomycin sulfate (NK 631) (author's transl)]

Pharmacological actions of pepleomycin sulfate (NK 631) which is a new antitumor agent derived from bleomycin were studied and the following results were obtained. NK 631 had no significant influences on the central, motor and sensory nervous systems at relatively higher doses (5 approximately 10 mg/kg, i.v., i.p., s.c.). NK 631 (5 approximately 10 mg/kg, i.v.) caused a slight decrease in blood pressure in anesthetized rats and slight increases in blood pressure, heart rate and peripheral blood flow in anesthetized dogs. NK 631 (1 approximately 3 mg) given close-arterially caused a slight increase in the developing tension in the isolated blood-perfused papillary muscle. NK 631 slightly contracted the isolated guinea pig ileum and rat uterus but did not affect the contraction of isolated guinea pig trachea. NK 631 caused significant increases in urine output and Cl excretion in saline loaded rats at 20 mg/kg, i.p. By the local injection of NK 631, a slight edema of rat paw and an increase in rabbit cutaneous permeability were observed. The intraperitoneal injection of NK 631 caused a significant increase in leakage of dye injected intravenously into the peritoneal cavity of mice. NK 631 did not affect hemolysis and prothrombin time at 10(-4) g/ml. In pharmacological actions, significant differences between NK 631 and pepleomycin were not observed.

A case report of surgical repair of traumatic rupture of the pericardium and diaphragm

A 55 year-old male with traumatic rupture of the pericardium, diaphragm and spleen, and with crush of the pancreas was successfully operated upon. The diagnosis of rupture of the diaphragm was done on the chest X ray on admission, and the rupture of the pericardium was diagnosed at the time of laparotomy and thoracotomy. The ruptured spleen and the crushed pancreas tail were removed, and the ruptured pericardium and diaphragm were closed successively.

beta-Adrenoceptor stimulation of exocrine secretion from the rat pancreas

1 Effects of catecholamines given intravenously on exocrine secretion from the pancreas were investigated in anaesthetized rats. The flow rate of pancreatic juice under resting conditions was 11.1 +/- 3.2 microliter per hour in 100 animals. 2 Dopamine (0.3--3 mg/kg) and isoprenaline (1--10 microgram/kg) induced almost the same increase in the pancreatic secretion, so that dopamine was 300 times less potent than isoprenaline. The relative potency of the two amines for stimulation of pancreatic secretion was equivalent to that for beta-stimulation of the contractile force of the left ventricle in vivo. 3 Propranolol (0.5 mg/kg) antagonized completely the dopamine- and isoprenaline-induced stimulation of the pancreatic secretion. 4 Haloperidol (10 mg/kg) failed to suppress the secretory effect of dopamine on the exocrine pancreas but abolished the dopamine-induced hypotension. 5 The dopamine-induced secretion was not modified by atropine (3 mg/kg), phenoxybenzamine (3 mg/kg), vagotomy or pithing. 6 Adrenaline and noradrenaline (10 microgram/kg) induced secretion after phenoxybenzamine treatment (3 mg/kg). 7 It is suggested that the rat pancreas has a stimulatory beta-adrenoceptor mechanism of exocrine secretion.

Species difference in the secretory response to dopamine in the pancreas of dogs, cats, rabbits and rats

The effects of dopamine and L-dopa on the exocrine secretion of the pancreas were compared in rats, cats, rabbits and dogs. Dopamine and its precursor, L-dopa, induced a secretin-like stimulation in dogs, while their effects were significantly less in rats. The dopaminergic receptor stimulus was involved in the exocrine secretion of the pancreas in dogs, whereas in rats, the beta-adrenergic receptor was involved. Spontaneous secretion in the resting state was present in rabbits but absent in cats. This spontaneous secretion in rabbits could be definitely inhibited by either dopamine or L-dopa. The secretin-induced secretion in both rabbits and cats was markedly inhibited by either dopamine or L-dopa. Species difference in the secretory response to dopamine in the pancreas of dogs, cats, rabbits and rats may be ascribed to the difference in the incorporation of exogenous L-dopa and dopamine in the exocrine cells of the pancreas.

Studies on sodium and calcium contents of cardiovascular tissue in experimental hypertension

Sodium and calcium contents of cardiovascular tissue in spontaneously hypertensive rats (SHR) and DOCA hypertensive rats were investigated. The effect of salt loading on these contents of SHR and control Wistar rats was also investigated. Calcium content increased with the development of hypertension, but not sodium content particularly in salt loading rats and at the sustained stage of DOCA hypertensive rats. These results suggest that calcium rather than sodium is more intimately related to the increase in blood pressure.

Reversible adrenergic alpha-receptor blocking action of 2,4'-dimethyl-3-piperidino-propiophenone (tolperisone)

The vascular action of 2,4'-dimethyl-3-piperidino-propiophenone hydrochloride (tolperisone hydrochloride), a centrally acting muscle relaxant, was investigated in pentobarbital anesthetized dogs. Tolperisone given intravenously produced a transient hypotension, tachycardia, and hyperventilation. The drug increased the femoral arterial flow, and decreased the superior mesenteric arterial flow following an initial transient increase. When injected directly into femoral and mesenteric arteries, tolperisone caused a rapid increase in both arterial flow (vasodilatation). However, femoral vessels were about 90 times as sensitive as mesenteric vessels to tolperisone. These results indicate that tolperisone shifts the blood volume from mesenteric (visceral) vessels to femoral (skeltal) ones. The femoral vasodilatation produced by i.a. tolperisone was not depressed by the pretreatment with i.a. propranolol, atropine or chlorphenylamine. Tolperisone decreased the contractile force in an isolated and cross-circulated papillary muscle. Tolperisone produced adrenaline reversal and antagonized the pressor response to noradrenaline. Moreover, femoral vasoconstriction caused by i.a. adrenaline was converted to vasodilatation and that caused by i.a. noradrenaline was depressed during an i.a. infusion of tolperisone. These results indicate that tolperisone blocks adrenergic alpha-receptors. The blocking action was rapid in onset, short-lived, and in addition, competitive.

[Effects of fusaric acid and its derivative on the cardiovascular system]

The cardiovascular effects of fusaric acid, a dopamine-beta-hydroxylase (DBH) inhibitor and a hypotensive agent, and 5-(4'-chlorobutyl) picolinic acid, one of the most potent DBH inhibitors in fusaric acid derivatives, were investigated in anesthetized dogs. Fusaric acid (10-30 mg/kg) given intravenously caused immediately and dose-dependently a fall in blood pressure, an increase in heart rate, a stimulation of respiration, a marked increase in the rate of superior mesenteric arterial flow, and a decrease in the rate of femoral arterial flow. Fusaric acid (0.3-3 mg) given close-arterially caused a dose-dependent decrease in the sinus rate and in the developed tension in isolated blood-perfused sinoatrial node and papillary muscle preparations, respectively. For the superior mesenteric, renal, and femoral circulations which were perfused with blood, a close-arterial injection of fusaric acid (10-30 mg) increased in the rates of flow in a dose-dependent manner. 5-(4'-Chlorobutyl) picolinic acid showed similar responses as fusaric acid quantitatively or qualitatively. These results indicate that hypotension induced rapidly after intravenous administration of fusaric acid or 5-(4'-chlorobutyl) picolinic acid is not due to the enzyme inhibition, but rather to the direct depression of cardiac function and decrease in peripheral vascular resistance.