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H T Yang

Publications and source records attributed to H T Yang.

At least 55 records · Page 3Linked to original sources
PubMed1995

Identification of murine loci associated with susceptibility to chronic experimental autoimmune encephalomyelitis.

B10.RIII mice develop chronic and relapsing experimental autoimmune encephalomyelitis (EAE) after immunization with the myelin basic protein (MBP) peptide 89-101. The disease is associated with the major histocompatibility complex (MHC) (eae1). We have now investigated the importance of non-MHC regions for the EAE susceptibility in a cross between RIIIS/J and B10.RIII mice which share the MHC region but differ in disease susceptibility. Linkage analysis using microsatellite markers spanning the genome identified a region (eae2) on chromosome 15 which showed linkage to disease (P = 0.0002). Our data also suggest linkage to a second region (eae3) on chromosome 3 (P = 0.0024), and provide evidence for locus interactions between eae2 and eae3. These results provide clues to the genetic basis of multiple sclerosis.

Amino Acid Sequence↗
PubMed1995

Training increases collateral-dependent muscle blood flow in aged rats.

The potential for physical training to enhance collateral-dependent blood flow (BF) to the hindlimbs of aged male rats (Fischer 344) was evaluated following bilateral femoral artery ligation at 20.5 mo of age. Rats were either limited to cage activity (sedentary, n = 11) or trained by a mild-intensity treadmill program (trained, n = 14), which involved walking twice a day at 15 m/min (15% grade) to fatigue, 5 days/wk for 8-11 wk. Exercise tolerance of the trained rats increased from approximately 5 to approximately 25 min/bout by week 7, whereas exercise tolerance of the sedentary group changed little (to approximately 8 min/bout) during the training period. At approximately 23 mo age, animals were surgically prepared for hindquarter perfusion (aortic pressure = 100 +/- 1.3 mmHg) and force measurement of the left gastrocnemius-plantaris-soleus (GPS) muscle group during isometric contractions at 4, 8, 15, 30, and 45 tetani/min via sciatic nerve stimulation (approximately 6 V, 0.1-ms square waves at 100 Hz for 100 ms). Although initial force development was similar between groups (12.9 N/g), trained rats maintained tension better at 8, 15, 30, and 45 tetani/min (P < 0.01). BF to the entire hindlimb of the trained group, determined with 85Sr 15-microns microspheres, was 43% greater (P < 0.05) than in the sedentary group. Thus collateral-dependent BF was improved by physical training. The greatest increase in BF was to the distal limb muscles (approximately 78%), the tissues most at risk during intermittent claudication.(ABSTRACT TRUNCATED AT 250 WORDS)

Adaptation, Physiological↗
PubMed1995

Heparin increases exercise-induced collateral blood flow in rats with femoral artery ligation.

The potential for heparin to enhance the training-induced increase in collateral-dependent blood flow to the distal hind-limb muscles was evaluated after bilateral femoral artery ligation in adult male rats (approximately 350 g). Rats received either saline (n = 34) or heparin (n = 36) injections and were kept sedentary (limited to cage activity) or exercised on a treadmill 5 days per week up a 15% incline by one of two protocols: (1) exercise at a constant moderate speed (20 m/min) for approximately 6 wks or (2) exercise at a progressively increased speed for 7 to 8 weeks (started at 20 m/min, increased at 15 minutes to 25 m/min, and then increased at 30 minutes to 30 m/min). Heparin- and saline-treated rats, exercised by the moderate-speed protocol, were run for the same time each day. Collateral-dependent blood flow to the distal limb tissue was determined by using 15-microns 85Sr-labeled microspheres in an isolated hindquarter preparation perfused in the descending aorta at 100 mm Hg. For comparison with the above groups, sedentary animals with acute femoral artery ligation and without femoral obstruction were included. Exercise tolerance increased from approximately 7 minutes initially to 30 to 40 minutes per bout; tolerance was greater in the heparin-injected rats than in the saline-injected rats (P < .05). Muscle performance of the gastrocnemius-plantaris-soleus muscle group (GPS) during isometric contractions in situ improved with training, was further increased by heparin administration (P < .001), and generally scaled with recovery of blood flow.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1994

Angiotensin-converting enzyme inhibition increases exercise tolerance and muscle blood flow in rats with peripheral arterial insufficiency.

To determine the effect of angiotensin-converting enzyme (ACE) inhibition on exercise tolerance and muscle blood flow (BF) to ischemic limbs, both femoral arteries of male Sprague-Dawley rats (approximately 325 g) were surgically stenosed. Rats were either active (treadmill run, 20 m/min (a) 15% grade, 5 d/wk for 3 wk) or sedentary (limited to cage activity), and assigned to one of three doses of zabicipril at 0.0 (zero), 0.3 (low), and 3.0 (high) mg.kg-1.d-1 administered via food intake (N = 14-15/group). After 3 weeks, the left carotid and caudal arteries were catheterized under anesthesia for BF measurement later in the day. Muscle BF was determined during exercise at two treadmill speeds (20 and 30 m/min) with 85Sr and 141Ce labeled microspheres to ensure a peak BF. Plasma ACE was inhibited 31%, 65% in the low- and high-dose sedentary rats and 75%, 74% in the low- and high-dose active animals, respectively (P < 0.001). Angiotensin-converting enzyme inhibition improved exercise tolerance by 3 weeks, at a low speed (20 m/min) in the sedentary groups (P < 0.025) and in a dose-dependent manner at a higher speed (25 m/min) in the active groups (P < 0.001). Blood pressures and heart rates during running were not different among groups. However, total hindlimb BF, reduced to approximately 33% of normal by femoral stenosis, was increased by ACE inhibition and chronic activity in a dose-dependent manner (P < 0.025). Blood flows to the plantar flexors were most improved (approximately 20-40%; to 124 mL.min-1 x 100 g-1) in the high-dose groups (P < 0.01). The higher run speed did not increase BF above the low speed. Training adaptation, indicated by an enhanced muscle mitochondrial content (P < 0.001), was similar for low- and high-dose active animals. Our results indicate that ACE inhibition improves BF to ischemic muscles and, together with chronic physical activity, improves exercise tolerance. The results from this study support those advocating ACE inhibition in managing appropriate patients with peripheral arterial insufficiency.

Angiotensin-Converting Enzyme Inhibitors↗
PubMed1994

Peripheral adaptations in trained aged rats with femoral artery stenosis.

The development and functional significance of exercise-induced peripheral adaptations were evaluated in aged animals with peripheral arterial insufficiency. Fisher 344 male rats (21 months old) were subjected to bilateral stenosis of the femoral arteries sufficient to limit active hyperemia but not to impair resting blood flow. Beginning the third day after stenosis, animals were (1) exercised by walking (n = 12) on a treadmill at 20 m/min at 15% inclination, twice a day, 5 days per week, or (2) limited to cage activity (n = 10). Exercise tolerance improved from approximately 5 to approximately 35 minutes (P < .001) over the 8 weeks of the training program but increased only marginally to approximately 8 minutes for the sedentary group. An isolated hind limb preparation perfused at equivalent blood flows (approximately 1 ml.min-1 x g-1 with an arterial blood oxygen content of approximately 20 vol%) was used to assess the functional and metabolic impact of muscle-specific adaptations during sequential contraction periods at 4, 8, 15, 30, 45, 60, 75, and 90 tetani per minute. An initially similar force development of approximately 10 N/g was better maintained (P < .001) by the trained group. The peak oxygen consumption attained by the trained group of 5.68 +/- 0.34 mumol.min-1 x g-1 was greater (P < .01) than that of the sedentary group (4.34 +/- 0.29 mumol.min-1 x g-1). This was due to a greater oxygen extraction, since oxygen delivery was the same (approximately 10 mumol.min-1 x g-1) to muscles of both groups.(ABSTRACT TRUNCATED AT 250 WORDS)

Adaptation, Physiological↗
PubMed1994

Dissociation of the positive inotropic effect of methoxamine from the hydrolysis of phosphoinositide in rabbit ventricular myocardium: a comparison with the effects of phenylephrine and the subtype of the alpha-1 adrenoceptor involved.

The effects of methoxamine on the contractile force and the hydrolysis of phosphoinositide (PI) were examined and compared with those of phenylephrine in the rabbit ventricular myocardium. Methoxamine, as well as phenylephrine, caused the concentration-dependent accumulation of [3H]inositol monophosphate in rabbit ventricular slices. The maximal responses of the two drugs were equivalent, but methoxamine was approximately 10 times less potent than phenylephrine. The extents and time courses of accumulation of [3H]inositol phosphates induced by 10(-4) M methoxamine and 10(-5) M phenylephrine were very similar, whereas the positive inotropic effect (PIE) of methoxamine developed much more slowly and its extent was much smaller than that of phenylephrine. The maximal inotropic response achieved with 10(-4) M methoxamine was one third of that achieved with phenylephrine. The PIE of methoxamine induced by a single administration was markedly attenuated when the same dose was given by cumulative administration. The concentration-response curve for the PIE of phenylephrine was shifted to the right and downward in the presence of methoxamine in a concentration-dependent manner. These results indicate that methoxamine accelerates the hydrolysis of PI as effectively as does phenylephrine, but it has a smaller PIE because of its depressant effect on the process subsequent to acceleration of the hydrolysis of PI induced by alpha-1 adrenoceptors. The accumulation of [3H]inositol 1,4,5-trisphosphate induced either by methoxamine or by phenylephrine was abolished by 10(-5) M chlorethylclonidine, whereas the maximal inhibition induced by WB 4101 was 60%.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1993

Myocardial alpha 1A-adrenoceptor subtypes in rabbit: differentiation by a selective antagonist, HV723.

The influence of a newly developed alpha 1-adrenoceptor antagonist, HV723 (alpha-ethyl-3,4,5-trimethoxy-alpha-(3-((2-(2-methoxy-phenoxy)ethyl)-ami no)- propyl) benzeneacetonitrile fumarate), on the positive inotropic effect and acceleration of phosphoinositide hydrolysis induced by phenylephrine via alpha 1-adrenoceptors in the presence of bupranolol (0.3 microM) was studied in the rabbit ventricular muscle: (1) HV723 at low concentrations (1-100 pM) attenuated the maximal inotropic response by 15-20% without altering the pD2 value for and [3H]inositol monophosphate accumulation induced by phenylephrine. The inhibitory action of HV723 (1-100 pM) showed a close resemblance to that of a selective alpha 1A antagonist, (+)-niguldipine. (2) HV723 (> or = 1 nM) shifted the concentration-response curve for phenylephrine to the right and downwards in association with a partial inhibition (42.5%) of [3H]inositol monophosphate accumulation. The IC50 values of HV723 for the inhibition of the inotropic response and phosphoinositide hydrolysis were approximately equal to the Kilow value determined by displacement of [3H]prazosin-specific binding. The mode of the inhibitory action of HV723 (> or = 1 nM) resembled that of another alpha 1A antagonist, WB 4101. These results indicate that HV723 shows a differential antagonistic action on the alpha 1A-mediated responses depending on the concentration: HV723 (1-100 pM) selectively inhibits the (+)-niguldipine-sensitive subclass to lead to a decrease in the maximal inotropic response with no change in phosphoinositide hydrolysis; HV723 (> or = 1 nM) may antagonize the WB 4101-sensitive subtype coupled to acceleration of phosphoinositide hydrolysis.

Acetonitriles↗
PubMed1993

Distribution and characterization of neuropeptide FF-like immunoreactivity in the rat nervous system with a monoclonal antibody.

Monoclonal antibodies against neuropeptide FF were produced and characterized. The antibodies are directed and highly specific to neuropeptide FF, and reactivity requires the C-terminal dipeptide of neuropeptide FF (Arg-Phe-NH2). Tissue extracts from bovine spinal cord, rat spinal cord and hypothalamus were analysed by high-pressure liquid chromatography coupled with radioimmunoassay using the characterized monoclonal antibody. Only one immunoreactive peptide was detected and it coeluted with authentic neuropeptide FF. Using this highly specific monoclonal antibody, the distribution of neuropeptide FF-like immunoreactivity was further studied by indirect immunohistochemistry. Immunoreactivity was seen in two major cell groups in the rat brain. The largest cell group was located in the medial hypothalamus between the dorsomedial and ventromedial nuclei. The other one was found in the nucleus of the solitary tract. Fibres immunoreactive for neuropeptide FF were located in the lateral septal nucleus, amygdala, different hypothalamic areas, nucleus of the solitary tract, ventral medulla, trigeminal complex and the dorsal horn of the spinal cord. Spinal and sympathetic ganglia were non-reactive. No neuropeptide FF immunoreactivity was seen in the gut autonomic nervous system or endocrine cells. The results show that neuropeptide FF-like immunoreactivity has a clearly more limited distribution in the nervous system than typical brain-gut peptides.

Amino Acid Sequence↗
PubMed1993

Angiotensin-converting enzyme inhibition increases collateral-dependent muscle blood flow.

The purpose of this study was to evaluate the effect of angiotensin-converting enzyme (ACE) inhibition on collateral-dependent blood flow (BF) during exercise. Adult male Sprague-Dawley rats (approximately 320 g) were fed zabicipril, an ACE inhibitor, mixed with powdered food at 0.0, 0.3, and 3.0 mg.kg-1 x day-1 (n = 12/group) for 5-7 days. Under ketamine-acepromazine anesthesia, the carotid and caudal arteries were catheterized for BF determination, and both femoral arteries were ligated to remove the primary route for BF to the distal limb tissue. Later on the same day, collateral-dependent hindlimb BF was determined at two treadmill speeds (15 and 25 m/min at 15% grade) with 85Sr- and 141Ce-labeled 15-microns microspheres. Zabicipril ingestion induced 50 and 65% inhibition of plasma ACE activity in the low- and high-dose group, respectively (P < 0.001). ACE inhibition did not affect body weight, blood pressure, or heart rate of the rats during exercise. However, BFs to the total hindlimb were 44 and 36% higher (P < 0.001) in zabicipril-treated animals than in the zero-dose controls (approximately 45 ml.min-1 x 100 g-1). Furthermore, BFs to the proximal hindlimb, distal hindlimb, and gastrocnemius-plantaris-soleus group were 33-44% greater in drug-treated than in control animals (P < 0.025). Higher speed (25 m/min) failed to further increase muscle BF; therefore peak BFs were likely achieved. These results indicate that collateral-dependent BF was improved by ACE inhibition.(ABSTRACT TRUNCATED AT 250 WORDS)

Angiotensin-Converting Enzyme Inhibitors↗
PubMed1993

[Nested-polymerase chain reaction in detection of Helicobacter pylori in human dental plaque].

A nested polymerase chain reaction (N-PCR) for the specific detection of Helicobacter pylori (H. pylori) was developed with two primer pairs derived from the urease gene A of H. pylori. The N-PCR was used to detect all 21 H. pylori strains, including 20 clinical isolates and 1 reference strain (NCTC 14126), but failed to detect 12 other bacterial species. It was shown that the PCR assay is 100% specific. Tenfold serial dilution experiments revealed that N-PCR could detect as little as 0.1 fg DNA. Samples of dental plaque and stomach biopsies from 29 patients were collected. Gastric specimens were tested by N-PCR, and the results were compared with those of culture, urease test and histological examination (reference standard). H. pylori sequences were detected by PCR showing that 21 were positive. The dental plaque samples from 8 of the 21 patients who tasted positive of gastric biopsies were positive by N-PCR. However, none of 8 dental plaque samples from the patients whose gastric samples were negative showed amplification. Dual therapy was given to two patients who were H. pylori positive in gastric mucosa and dental plaque. One month after treatment, H. pylori was eradicated from the gastric mucosa, but persisted in dental plaque.

Adult↗
PubMed1993

[A study of anti-D'E polypeptide in the diagnosis of mixed connective tissue disease].

By using immunoblotting technique (IBT) and salt extracts of rabbit thymus powder as antigen, we detected autoantibodies against polypeptides of extractable nuclear antigen (ENA) in 358 patients with different rheumatic diseases. It was found that antibodies against polypeptides with molecular weights of 13,900 dalton (designated as D') and 11,500 dalton (designated as E) could be detected only in mixed connective tissue disease (MCTD) with a positive rate of 19.1%. These antibodies were termed collectively as anti-D'E polypeptide in this paper and shown to have high specificity for the diagnosis of MCTD (P < 0.001).

Antibodies, Antinuclear↗
PubMed1992

[Magnetic resonance imaging in diagnosing hypertrophic cardiomyopathy: an analysis of 10 cases].

Ten patients with hypertrophic cardiomyopathy (HCM) were examined with ECG-gated magnetic resonance imaging (MRI), one of whom was a child. MRI shows deformities of left ventricular cavity in all 10 patients, shapes of majority being long and narrow. Interventricular septums (IVS) were identically thickened in 5 patients, middle areas of IVS were thickened in 3 patients, local area of IVS was thickened in ball-shape in 1 patient, the apex was thickened in 1 patient. The ratio of thickened of IVS between in systole and diastole was less 1.08 in 5 patients and equal to 1.0 in 4 patients. The ratio of thickness of thickened left ventricular posterior wall between in systole and diastole was less than 1.25 in 7 patients. Ratios were respectively 1.25 and 1.53 in a child, obviously higher than those of adults. Left ventricular outflow tract was narrow in 1 patient. Left atria were enlarged in 7 patients. left ventricular diastolic function was damaged in 8 patients and systolic function was damaged in 1 patient. Signal intensity in IVS was not identical in 6 patients, of whom 3 patients suggests degenerate degree of myocardium in comparison with histology of myocardium. Proximal ends of coronary arteries were clear in 4 patients and didn't show narrow. All 10 patients were examined with UCG, 9 patients with ECT, 3 patients with ventricular angiography. All results coincide with features of HCM.

Adult↗
PubMed1991

Low-intensity training produces muscle adaptations in rats with femoral artery stenosis.

The effectiveness of a mild-intensity exercise program to induce adaptations within skeletal muscle of animals with peripheral arterial insufficiency was evaluated using an isolated perfused hindlimb preparation at a muscle blood flow similar to the peak found in vivo. Adult rats were subjected to bilateral femoral artery stenosis sufficient to limit peak blood flow during exercise but not alter resting blood flow. Stenosed-trained (Sten-Trained) rats walked on a treadmill at an easily achieved speed (20 m/min with a 15% grade) 5 days wk. Exercise tolerance improved from 10 min initially to 2 h/day. Non-stenosed-sedentary (Non-Sten-Sed) and stenosed-sedentary (Sten-Sed) animals were limited to cage activity. Oxygen delivery to the contracting muscles was similar among groups (7.0 +/- 0.4, 7.3 +/- 0.6, and 6.6 +/- 0.6 mumol.min-1.g-1 in Non-Sten-Sed, Sten-Sed, and Sten-Trained, respectively; n = 13 each). Force development was better maintained by Sten-Trained muscle (P less than 0.001) during a sequence of tetanic contraction conditions. Peak oxygen consumption was greater (P less than 0.05) in the Sten-Trained (5.23 +/- 0.34 mumol.min-1.g-1) than in Non-Sten-Sed (4.08 +/- 0.35) and Sten-Sed (4.34 +/- 0.37) rats. The increased peak oxygen extraction (P less than 0.05) by the muscle of the Sten-Trained rats (82.5 +/- 7.1% of oxygen inflow vs. 58.7 +/- 4.7 and 57.4 +/- 5.0%, respectively) was probably related to the increased muscle capillarity and mitochondrial enzyme activity.(ABSTRACT TRUNCATED AT 250 WORDS)

Adaptation, Physiological↗
PubMed1990

The influence of pentoxifylline and torbafylline on muscle blood flow in animals with peripheral arterial insufficiency.

The potential of pentoxifylline to enhance blood flow to relatively ischemic muscle during running was evaluated in rats with peripheral arterial insufficiency. Femoral artery stenosis, sufficient to limit exercise hyperemia but not affect resting blood flow, was surgically induced in adult male rats (approximately 350 g). Day three after stenosis, rats were assigned to either a control (N = 14) or treatment (N = 14) group and exercised 5 days a week for 3 weeks. Exercise tolerance of rats fed pentoxifylline (34 +/- 1.3 mg/kg/day) or an analog (torbafylline; 34 +/- 2.3 mg/kg/day) increased more (P less than .001) than control rats in the third week of treatment. This was evidenced by a higher treadmill speed and longer duration of running. Blood flows determined with 85Sr and 141Ce labeled 15 mu spheres at low (20 m/min) and high (30-35 m/min) treadmill speeds were similar for each group and approximately 50% of that found in normal nonstenosed rats. Blood flows to the entire hindlimb, to the proximal and distal hindlimb segments, and to individual muscle fiber sections were not different between control and pentoxifylline groups. Thus, the increase in exercise tolerance could not be attributed to an increase in muscle blood flow. Rather, an enhanced oxygen extraction by the working limb muscles should lead to the increased VO2, required by the faster running speed in the pentoxifylline rats. This suggests that pentoxifylline may act to improve microvascular flow heterogeneity in working muscle. Our findings support clinical evidence that pentoxifylline is effective in managing patients with peripheral arterial insufficiency.

Animals↗
PubMed1990

Training increases muscle blood flow in rats with peripheral arterial insufficiency.

This study investigated the effect of physical training on muscle blood flow (BF) in rats with peripheral arterial insufficiency during treadmill running. Bilateral stenosis of the femoral artery of adult rats (300-350 g) was performed to reduce exercise hyperemia in the hindlimb but not limit resting muscle BF. Rats were divided into normal sedentary, acute stenosed (stenosed 3 days before the experiment), stenosed sedentary (limited to cage activity), and stenosed trained (run on a treadmill by a progressively intense program, up to 50-60 min/day, 5 days/wk for 6-8 wk). Hindlimb BF was determined with 85Sr- and 141Ce-labeled microspheres at a low (20 m/min) and high treadmill speed (30-40 m/min depending on ability). Maximal hindlimb BF was reduced to approximately 50% normal in the acute stenosed group. Total hindlimb BF (81 +/- 5 ml.min-1.100 g-1) did not change in stenosed sedentary animals with 6-8 wk of cage activity, but a redistribution of BF occurred within the hindlimb. Two factors contributed to a higher BF to the distal limb muscle of the trained animals. A redistribution BF within the hindlimb occurred in stenosed trained animals; distal limb BF increased to approximately 80% (P less than 0.001) of the proximal tissue. In addition, an increase in total hindlimb BF with training indicates that collateral BF has been enhanced (P less than 0.025). The associated increase in oxygen delivery to the relatively ischemic muscle probably contributed to the markedly improved exercise tolerance evident in the trained animals.

Animals↗
PubMed1990

[Effect of naphthylmethyl isoquinoline on the isolated guinea pig myocardium].

The effect of naphthylmethyl isoquinoline on amplitude of contraction and automaticity of guinea pig atria were investigated. The compound was found to markedly inhibit the force of contraction and automaticity in a concentration-dependent way. Propranolol competitively antagonized the effect of isoproterenol with pA2 of 7.5. Naphthylmethyl isoquinoline and verapamil antagonized isoproterenol, but in a noncompetitive manner with the pD2' of 5.4 and 5.8, respectively. The effect of the compound on action potential and contractile force of guinea pig papillary muscles were also studied. It was shown to produce negative inotropic effects and shorten the fast action potential duration, but the maximal upstroke (Vmzx) and amplitude of action potential were not affected. Thus, an excitation-contraction uncoupling was observed. It also depressed the amplitude. Vmax and duration of Ca2(+)-mediated slow action potential induced by high K+. Elevation of the CaCl2 concentration from 2 to 5 mmol/L reversed its inhibition partially. These results indicate that naphthylmethyl isoquinoline has a blocking effect on calcium channels.

Action Potentials↗
PubMed1990

[Hypotensive effect of naphthylmethyl isoquinoline].

Naphthylmethyl isoquinoline (NI), a modified structure of tetrandrine, was synthesized by the China Pharmaceutical University. The effects of NI on blood pressure of animals and its possible mechanism were studied. In anesthetized rats and cats, iv NI lowered the mean arterial pressure. Meanwhile, the total peripheral vascular resistance was reduced markedly, but the heart rate, cardiac output and cardiac index showed no noticeable change. In rats its hypotensive effect was stronger than tetrandrine when equal toxic doses were compared. In conscious normotensive rats, renal hypertensive rats and SHR, oral administration of this compound resulted in a marked fall of systolic blood pressure which remained at a steady low level. It decreased the pressor response of adrenaline in rats. Intra-arterial injection of NI into the perfusing system decreased the posterior limb and renal vascular resistance immediately in constant-rate perfusion of the posterior limb and renal blood vessel of rats. It shifted the cumulative dose-response curves of noradrenaline, KCl and CaCl2 to the right in isolated rabbit aortic rings and depressed their maximal responses with IC50 9.7, 7.2 and 1.6 mumol/L, respectively, which were 2.9, 9.1 and 1.8 times stronger than that of tetrandrine, correspondingly. These results suggest that the hypotensive effect of naphthylmethyl isoquinoline is mainly attributable to its arteriolar dilatation by inhibiting calcium influx.

Animals↗