Solvothermal synthesis of superhydrophobic hollow carbon nanoparticles from a fluorinated alcohol.

A new and simple method of synthesizing fluorinated carbon at the gram scale is presented by reacting a fluorinated alcohol with sodium at elevated temperatures in a sealed Teflon reactor. The resulting carbon nanoparticles are around 100 nm in diameter, and display a hollow shell morphology, with a significant amount of fluorine doped into the carbon. The nanoparticles disperse easily in ethanol, and are thermally stable up to 400 °C and 450 °C under air and nitrogen, respectively. The nanoparticle dispersion was printed onto various substrates (paper, cloth, silicon), inducing superhydrophobicity.

Interlayer structure and self-healing in suspensions of brush-stabilized nanoplatelets with smectic order.

We have investigated the rheology of an uncured epoxy fluid containing high aspect ratio (length/thickness ≈ 160) α-zirconium phosphate (ZrP) nanoplatelets with smectic order. The nanoplatelets were exfoliated into monocrystalline sheets with uniform thickness using a monoamine-terminated oligomer. The oligomers were densely grafted to the plate surfaces and behave as a molecular brush. Suspensions containing ∼ 2 vol.% ZrP and above show liquid crystalline order with scattering peaks characteristic of a smectic (layered) mesophase. At much higher loading, ∼ 4 vol.% ZrP, there is a sharp transition in visual appearance, steady shear rheology, and linear and non-linear viscoelasticity that is attributed to the reversible interdigitation of oligomer chains between closely spaced layers. The oligomers are proposed to serve as inter-lamellar bridges that store elastic stresses for intermediate rates of deformation, but are able to relax on longer time scales. Under steady shearing conditions, the smectic suspensions with "overlapped" microstructure show a discontinuous flow curve characteristic of shear banding that is attributed to the dynamic pull-out of oligomer chains from the overlap region. At high shear rates, the limiting viscosity of the concentrated suspensions is on the same order of magnitude as the unfilled suspending fluid. When the rate of deformation is reduced below a critical time scale, the original network strength, and corresponding microstructure, is recovered through a passive self-healing process. The unique combination of concentration-dependent yield stress, low post-yield viscosity, and self-healing is potentially useful for various applications in the liquid state, and desirable for scalable processing of nanocomposite materials for structural applications.

Long-term blockade of L/N-type Ca(2+) channels by cilnidipine ameliorates repolarization abnormality of the canine hypertrophied heart.

BACKGROUND AND PURPOSE: The heart of the canine model of chronic atrioventricular block is known to have a ventricular electrical remodelling, which mimics the pathophysiology of long QT syndrome. Using this model, we explored a new pharmacological therapeutic strategy for the prevention of cardiac sudden death. EXPERIMENTAL APPROACH: The L-type Ca(2+) channel blocker amlodipine (2.5 mg.day(-1)), L/N-type Ca(2+) channel blocker cilnidipine (5 mg.day(-1)), or the angiotensin II receptor blocker candesartan (12 mg.day(-1)) was administered orally to the dogs with chronic atrioventricular block for 4 weeks. Electropharmacological assessments with the monophasic action potential (MAP) recordings and blood sample analyses were performed before and 4 weeks after the start of drug administration. KEY RESULTS: Amlodipine and cilnidipine decreased the blood pressure, while candesartan hardly affected it. The QT interval, MAP duration and beat-to-beat variability of the ventricular repolarization period were shortened only in the cilnidipine group, but such effects were not observed in the amlodipine or candesartan group. Plasma concentrations of adrenaline, angiotensin II and aldosterone decreased in the cilnidipine group. In contrast, plasma concentrations of angiotensin II and aldosterone were elevated in the amlodipine group, whereas in the candesartan group an increase in plasma levels of angiotensin II and a decrease in noradrenaline and adrenaline concentrations were observed. CONCLUSIONS AND IMPLICATIONS: Long-term blockade of L/N-type Ca(2+) channels ameliorated the ventricular electrical remodelling in the hypertrophied heart which causes the prolongation of the QT interval. This could provide a novel therapeutic strategy for the treatment of cardiovascular diseases.

Antigenic stimulation with cytochrome P450 2J expressed in mouse hepatocellular carcinoma cells regulates host anti-tumour immunity.

Cytochrome P450 2J subfamily (CYP2J) enzymes expressed in mouse hepatocellular carcinoma (HCC) cells were identified as an antigen recognized by specific CD4(+) T cells and the structure of its T cell epitope was determined by proteomics-based exploration. The major histocompatibility complex (MHC) class II binding peptides were isolated from I-A(k)/peptide complex of dendritic cells (DCs) loaded or unloaded with MIH-2 mouse HCC cells. MHC class II-binding peptides found in MIH-2-loaded DCs but not in unloaded DCs were determined by tandem mass spectrometric analysis. The peptide, consisting of amino acid 276-290 (DFIDAFLKEMTKYPE) of mouse CYP2J enzymes, was identified as an antigenic peptide presented in the context of MHC class II. Preventive treatment of mice with CYP2J peptide stimulated interferon (IFN)-gamma production of splenocytes and suppressed the growth of implanted CYP2J-positive MIH-2 cells but not CYP2J-negative murine bladder tumour cells. However, continuous treatment of MIH-2-bearing mice with CYP2J peptide significantly suppressed IFN-gamma production of splenocytes and accelerated the growth of implanted MIH-2 tumours in vivo. Increased frequencies of CD4(+)forkhead box P3 regulatory T cells and CD11b(+)Gr-1(+) myeloid suppressor cells were observed in splenocytes from the continuously immunized mice. These results indicate that antigenecity of CYP2J isoforms expressed in HCC cells activate host anti-tumour immunity at an initial stage of HCC, but suppress host anti-tumour immunity with excessive antigenic stimulation at an advanced stage.

No proarrhythmic properties of the antibiotics Moxifloxacin or Azithromycin in anaesthetized dogs with chronic-AV block.

BACKGROUND & PURPOSE: The therapeutically available quinolone antibiotic moxifloxacin has been used as a positive control for prolonging the QT interval in both clinical and non-clinical studies designed to assess the potential of new drugs to delay cardiac repolarization. Despite moxifloxacin prolonging QT, it has not been shown to cause torsades de pointes arrhythmias (TdP). Azithromycin is a macrolide antibiotic that has rarely been associated, clinically, with cases of proarrhythmia. As there is a lack of clinical data available, the cardiac safety of these drugs was assessed in a TdP-susceptible animal model by evaluating their repolarization and proarrhythmia effects. EXPERIMENTAL APPROACH & KEY RESULTS: In transfected HEK cells, the IC(50)s for I (hERG) were 45+/-6 and 856+/-259 microg ml(-1) for moxifloxacin and azithromycin, respectively. Intravenous administration of 2 and 8 mg kg(-1) moxifloxacin (total peak-plasma concentrations 4.6+/-1.5 and 22.9+/-6.8 microg ml(-1)) prolonged the QT(c) in 6 anaesthetized dogs with chronic AV block by 7+/-3 and 21+/-19%, respectively. Similar intravenous doses of azithromycin (total peak-plasma concentrations 5.4+/-1.3 and 20.8+/-4.9 microg ml(-1)) had no electrophysiological effects in the same dogs. The reference compound, dofetilide (25 microg kg(-1) i.v.) caused QT(c) prolongation (29+/-15%) and TdP in all dogs. Beat-to-beat variability of repolarization (BVR), quantified as short-term variability of the left ventricular monophasic action potential duration, was only increased after dofetilide (1.8+/-0.7 to 3.8+/-1.5 ms; P<0.05). CONCLUSION & IMPLICATIONS: As neither moxifloxacin nor azithromycin caused TdP or an increase in the BVR, we conclude that both drugs can be used safely in clinical situations.

Cardiac electrophysiologic and hemodynamic effects of sildenafil, a PDE5 inhibitor, in anesthetized dogs.

A recent in vitro study demonstrated that supratherapeutic concentrations of sildenafil, a phosphodiesterase type 5 (PDE5) inhibitor, blocked I(Kr) and prolonged cardiac repolarization. This study assessed the in vivo cardiohemodynamic and electrophysiologic effects of sildenafil using a halothane-anesthetized, closed-chest canine model (n = 5) to bridge the gap between basic observation and clinical experience. Intravenous administration of sildenafil citrate in doses of 0.03, 0.3, and 3.0 mg/kg for 10 min, which provided sub-to supratherapeutic plasma drug concentrations, did not affect the monophasic action potential duration or effective refractory period of the right ventricle during the sinus rhythm as well as the ventricular pacing at the cycle length of 400 and 300 ms. However, sildenafil decreased the total peripheral resistance, simultaneously inducing positive chronotropic and inotropic effects at the top dose, which gave plasma concentrations at least 10 times higher than the therapeutic range. This cardiohemodynamic profile of sildenafil can be largely explained by reflex sympathetic activation associated with its vasodilator effect. Meanwhile, the lack of prolongation of the ventricular repolarization phase at the therapeutically relevant to moderately supratherapeutic sildenafil concentrations supports the earlier clinical studies that indicate that sildenafil has no effect on electrocardiogram.

In vivo antiarrhythmic profile of AP-792 assessed in different canine arrhythmia models.

The antiarrhythmic effects of a novel antiarrhythmic drug AP-792, 4-(5H-dibenzo[a,d]cyclohepten-5-ylidene)-1-[4-cyclohexylbutyl]piperidine hydrochloride, were analyzed using the epinephrine-, digitalis- and two-stage coronary ligation-induced canine ventricular arrhythmia models. Intravenous administration of AP-792 (0.3 or 1.0 mg/kg) effectively suppressed each of the ventricular arrhythmias, an action that resembles that of a typical cardioselective Ca2+ channel blocker, AH-1058. The antiarrhythmic action of AP-792 was slow in onset and longer-lasting than those in our previous studies using more than 50 antiarrhythmic drugs, including Na+ and Ca2+ channel blockers. These results suggest that AP-792 can become a unique long-acting antiarrhythmic drug.

Utilization of telemetry system to assess the cardiovascular profile of AH-1058, a new cardioselective Ca2+ channel blocker, in conscious dogs.

Cardiovascular effects of a new Ca2+ channel blocker AH-1058, 4-(5H-dibenzo[a,d]cyclo-hepten-5-ylidene)-1-[(E)-3-(3-methoxy-2-nitro)phenyl-2-propenyl]piperidine hydrochloride, were assessed in conscious dogs using a new telemetry system. AH-1058 (0.03, 0.1 and 0.3 mg/kg, i.v.) reduced systolic blood pressure and the maximal upstroke velocity of the left ventricular pressure and increased the heart rate in a dose-dependent manner without affecting the diastolic blood pressure; each of these responses lasted for several hours. These results support the previous knowledge that AH-1058 is a long-lasting cardiodepressive drug. The telemetry system provided important information for predicting favorable clinical effects of AH-1058.

Cardiovascular action of a cardioselective Ca(2+)channel blocker AH-1058 in conscious dogs assessed by telemetry.

AH-1058, 4-(5H-Dibenzo[a,d]cyclohepten-5-ylidene)-1-[(E)-3-(3-methoxy-2-nitro)phenyl-2-propenyl]piperidine hydrochloride, is a novel Ca(2+)channel blocker exerting cardioselective action in isolated or anesthetized canine heart preparations. To clarify the cardiac and hemodynamic action of AH-1058 in conscious dogs, we assessed the effects of the drug on the hemodynamic parameters continuously recorded by telemetry in conscious unrestrained beagle dogs, and its cardiovascular effects were compared with those of verapamil, disopyramide and atenolol. Oral administration of AH-1058 (0.15, 0.3 and 0.6 mg/kg) reduced the systolic blood pressure and maximal upstroke velocity of the left ventricular pressure (LVdP/dt(max)), increased heart rate and prolonged the QA interval in a dose-dependent manner whereas the drug did not affect diastolic blood pressure. Verapamil at 10 mg/kg reduced systolic and diastolic blood pressure with little effect on heart rate, LVdP/dt(max) and QA interval. Disopyramide at 20 mg/kg increased systolic and diastolic blood pressure, decreased LVdP/dt(max) and prolonged the QA interval with little changes in heart rate. Atenolol at 10 mg/kg decreased LVdP/dt(max) and prolonged the QA interval with little changes in systolic blood pressure, diastolic blood pressure and heart rate. The time course of the cardiohemodynamic action of AH-1058 was longer than those of the other drugs. These results suggest that AH-1058 is a long-acting cardiodepressive drug, and its hemodynamic profile is obviously different from that of disopyramide and atenolol. This unique cardiovascular profile may be beneficial for the treatment of certain pathological processes in which selective inhibition of the ventricular Ca(2+)channels would be the target of drug therapy.

Effects of a dual L/N-type Ca(2+) channel blocker cilnidipine on neurally mediated chronotropic response in anesthetized dogs.

We investigated the effects of an L-type and N-type Ca(2+) channel blocker, cilnidipine, on neurally mediated chronotropic responses to clarify the anti-autonomic profile of cilnidipine in anesthetized dogs. Pretreatment with cilnidipine (0.3, 1.0 and 3.0 microg/kg, i.v.), which decreased mean blood pressure by 5 to 31 mm Hg, inhibited the changes in heart rate and plasma norepinephrine concentration induced by bilateral carotid artery occlusion, whereas it had no effect on vagal nerve stimulation-induced bradycardia. These results suggest that antihypertensive and antisympathetic doses of cilnidipine fail to influence chronotropic responses mediated by parasympathetic nerve activation in the in vivo canine heart.

AH-1058: a novel cardioselective Ca2+ channel blocker.

The pharmacologic profile of a cyproheptadine-related compound, 4-(5H-dibenzo[a,d]cyclohepten-5-ylidene)-1-[(E)-3-(3-methoxy-2-nitro)phenyl-2-propenyl]piperidine hydrochloride (AH-1058), was assessed in various in vivo and in vitro models. In guinea pig cardiomyocytes, AH-1058 effectively suppressed L-type Ca2+ channel currents without affecting other ion channel or ion exchange currents. In rat cerebral cortical membranes AH-1058 appears to bind preferentially to L-type Ca2+ channels at phenylalkylamine- and benzothiazepine-binding sites. In canine isolated, blood-perfused heart preparations, AH-1058 exerted negative inotropic, dromotropic, and chronotropic and weak coronary vasodilator effects. In halothane-anesthetized dogs, AH-1058 suppressed ventricular contractility and decreased blood pressure and cardiac output. Total peripheral vascular resistance was hardly affected by the drug, suggesting that in vivo AH-1058 can selectively suppress cardiac, as compared to peripheral vascular, function. In conscious dogs, by intravenous administration AH-1058 reduced systolic blood pressure and maximal upstroke velocity of the left ventricular pressure, while it increased heart rate in a dose-dependent manner. The drug did not affect diastolic blood pressure, which is quite different from cardiovascular properties of well-known Ca2+ channel blockers, verapamil and diltiazem. This unique cardiovascular profile of AH-1058 is expected to be useful in the treatment of certain pathological processes such as the obstructive hypertrophic cardiomyopathy, vasovagal syncope, dissecting aortic aneurysm, and ventricular arrhythmias, in which selective inhibition of the ventricular Ca2+ channels is essential for drug therapy.

Comparison of the electropharmacological effects of verapamil and propranolol in the halothane-anesthetized in vivo canine model under monophasic action potential monitoring.

The cardiovascular profile of verapamil was assessed in the halothane-anesthetized canine model and compared with that of propranolol. Verapamil was infused at the rates of 1, 3 and 10 microg x kg(-1) x min(-1) (n=6), whereas propranolol was administered at a fixed rate of 10 microg x kg(-1) x min(-1) (n=6). Each infusion was performed over 30 min, and the parameters were assessed for 20-30 min after the start of each infusion. Verapamil in a dose of 10 microg x kg(-1) x min(-1) significantly suppressed atrio-ventricular (AV) node conduction and slightly decreased the mean blood pressure, but no significant change was detected in the left ventricular end-diastolic pressure, maximum upstroke velocity of the left ventricular pressure, sinus automaticity, double product, cardiac output, intraventricular conduction, and ventricular repolarization phase and refractoriness. Propranolol suppressed AV node conduction to an extent similar to that of verapamil, but it also inhibited intraventricular conduction, sinus automaticity and ventricular contraction, increased the ventricular refractoriness, and decreased the double product and cardiac output, without any significant change in the other variables measured. These results suggest that verapamil can selectively affect the AV node, and that the greater part of the suppressive action of propranolol on the multiple cardiovascular performance is through a beta-blocking action and direct membrane effect, although the halothane inhalation itself might have modified each of the drug's effects. The abbreviation of the relative refractory period of the ventricle by propranolol may show its potential utility for re-entry type ventricular tachycardia.

Electrophysiological and cardiohemodynamic effects of AH-1058, a new type calcium channel blocker, assessed by the in vivo canine model.

AH-1058 (4-(5H-dibenzo[a, d]cyclohepten-5-ylidene)- 1-[(E)-3-(3-methoxy-2-nitro)phenyl-2-propenyl]piperidine hydrochloride) is a novel calcium channel blocker whose chemical structure is quite different from those of typical calcium channel blockers. In this study, electrophysiological and hemodynamic effects of AH-1058 were assessed in the halothane-anesthetized, closed-chest canine model. Intravenous administration of a canine antiarrhythmic dose of 100 microg/kg of AH-1058 (n = 6) did not affect the cardiovascular variables, except that the cardiac output was decreased at 30 min after the drug administration. Additional administration of 200 microg/kg of AH-1058 (n = 6) suppressed the sinus nodal automaticity, AV nodal conduction and ventricular contraction and decreased the mean blood pressure, cardiac output and double product. The effects gradually appeared, while no change was detected in the intraventricular conduction, ventricular repolarization period, ventricular effective refractory period, preload to the left ventricle and total peripheral vascular resistance during the observation period of 30 min. The cardiosuppressive effects of AH-1058 can be explained by its calcium channel blocking action demonstrated in a previous in vitro experiment, while the lack of the effect on the vascular resistance would suggest that AH-1058 may become a slow-acting cardioselective calcium channel blocker.

Effects of a novel vesamicol receptor ligand, m-(iodobenzyl)trozamicol, on the canine isolated, blood-perfused atrioventricular node preparation.

m-(Iodobenzyl)trozamicol (MIBT) is a recently discovered vesamicol analogue. It has been shown that radiolabelled [125I]MIBT can be used as a marker of cholinergic innervation in the heart as well as in the brain. The purpose of this study was to analyze the direct effects of MIBT on the atrioventricular and intraventricular conduction in addition to the coronary blood flow using the canine isolated, blood-perfused atrioventricular node preparation. Intracoronary administration of MIBT suppressed the atrioventricular and intraventricular conduction, while it increased the coronary blood flow. The effect and duration of action on the intraventricular conduction was less pronounced compared with other effects. Moreover, the doses of MIBT needed to cause negative dromotropic and coronary vasodilator effects in this study was much greater than those needed for imaging the cardiac cholinergic innervation. Pretreatment of the preparations with a muscarinic receptor antagonist, atropine, did not block these effects of MIBT, suggesting that MIBT may possess muscarinic receptor-independent ion channel activity in the cardiac conduction system and coronary arteries.

Antiarrhythmic and cardiohemodynamic effects of a novel Ca(2+) channel blocker, AH-1058, assessed in canine arrhythmia models.

The antiarrhythmic profile and cardiohemodynamic effect of a novel Ca(2+) channel blocker, 4-(5H-Dibenzo[a, d]cyclohepten-5-ylidene)-1-[(E)-3-(3-methoxy-2-nitro)phenyl-2-p ropeny l]piperidine hydrochloride (AH-1058), were analyzed using the epinephrine-, digitalis- and two-stage coronary ligation-induced canine ventricular arrhythmia models. Intravenous administration of AH-1058 (100 microg/kg) effectively suppressed each of the ventricular arrhythmias accompanied by weak hypotensive effects. The results contrast well with those of a typical Ca(2+) channel blocker, verapamil, which suppresses only the epinephrine-induced ventricular arrhythmia with severe hypotension. These results indicate that AH-1058 may possess a more selective inhibitory action on Ca(2+) channels in the heart than on those in the vessels. Furthermore, the antiarrhythmic actions of AH-1058 were slower in onset and longer-lasting, than those in our previous studies using other antiarrhythmic drugs, including Na(+) and Ca(2+) channel blockers. The antiarrhythmic effects of AH-1058 did not correlate with its plasma concentrations when administered either intravenously or orally. These results suggest that AH-1058 can become a long-acting Ca(2+) channel blocker with unique antiarrhythmic properties, and that AH-1058 may be used in certain pathological processes, for which selective inhibition of the cardiac Ca(2+) channels is essential.

Comparison of cardiovascular effects of a new calcium channel blocker AH-1058 with those of verapamil assessed in blood-perfused canine heart preparations.

The cardiovascular effects of AH-1058, a novel calcium channel blocker, were examined in comparison with those of verapamil using canine isolated, blood-perfused papillary muscle, atrioventricular node, and sinoatrial node preparations. Intravenous administration of AH-1058 (20, 50, and 100 microg/kg) or verapamil (20, 50, and 100 microg/kg) to the blood-donor dog induced negative inotropic, dromotropic, and chronotropic effects and a coronary vasodilator action in cross-circulated isolated heart preparations, simultaneously inducing the same cardiac effects in the blood-donor dog. The order of potency of the effects of AH-1058 was ventricular contraction > coronary blood flow >> atrioventricular conduction > sinoatrial automaticity, whereas that of verapamil was coronary blood flow >> atrioventricular conduction >> sinoatrial automaticity > ventricular contraction. The cardiosuppressive effects of AH-1058, especially on ventricular contraction, were slower in onset and longer lasting than those of verapamil. These results suggest that this unique cardiovascular profile of AH-1058 may become beneficial for the treatment of certain pathologic processes, in which selective inhibition of ventricular calcium channels would be essential for drug therapy.

Fall-related injuries in dementia with Lewy bodies (DLB) and Alzheimer's disease.

Repeated falls are reported as one of the clinical characteristics in dementia with Lewy bodies (DLB). We examined the incidence of fall-related injuries in 561 dementia patients with various clinical diagnoses, including DLB and Alzheimer's disease (AD), in a ward established for dementia research. The incidence of fall-related injuries was significantly higher in DLB patients (10.7%) than in AD patients (1.1%) (P < 0.001). The high incidence in those patients with DLB cannot be attributed to Parkinsonism because none of the DLB patients with injuries showed extrapyramidal sign. Our observations suggest that patients with a clinical diagnosis of DLB have a high risk of fall-related injuries, even though they do not show Parkinsonism. An appropriate clinical discrimination between DLB and AD is recommended to manage and prevent fall-related injuries.

In situ atomic force microscopic observation of albumin adsorption onto phase-separated organosilane monolayer surface.

A mixed (n-octadecyltrichlorosilane (OTS)/[2-(perfluorooctyl)ethyl]trichlorosilane (FOETS)) monolayer was prepared on the water subphase and was subsequently immobilized onto the silicon wafer surface by chemical bonds. Atomic force microscopic (AFM) observation of the mixed (OTS/FOETS) monolayer revealed the formation of a phase-separated structure. In situ AFM observation of the adsorption behavior of bovine serum albumin (BSA) onto the mixed (OTS/FOETS) monolayers, successfully showed the adsorption behavior of BSA onto the phase-separated surface. It also revealed that in the case of pH 7.5, BSA was preferentially adsorbed onto the lower surface free energy FOETS phase of the mixed (OTS/FOETS) monolayer. On the other hand, BSA was adsorbed homogeneously onto the OTS and FOETS phases at the isoelectric point of BSA (pI 4.7). These results indicate that the preferential adsorption of BSA onto the FOETS phase in the mixed (OTS/FOETS) monolayer system may be due to: (1) the minimization of interfacial free energy between a monolayer surface and an aqueous solution; and (2) the electrostatic repulsion among BSA molecules bearing negative charges.

Electrophysiologic, cardiohemodynamic and beta-blocking actions of a new ultra-short-acting beta-blocker, ONO-1101, assessed by the in vivo canine model in comparison with esmolol.

The purpose of this study was to assess the cardiovascular effects of an ultra-short-acting beta-blocker, ONO-1101, by using halothane-anesthetized beagle dogs in comparison with esmolol. ONO-1101 (n = 6) or esmolol (n = 6) was administered at four infusion rates of 0.3, 3, 30, and 300 microg/ kg/min. Each infusion was performed over a 30-min period, and the parameters were measured at 20-30 min after the start of each infusion. ONO-1101 significantly decreased the heart rate, rate-pressure product, left ventricular contraction, cardiac output, and relative refractory period of the right ventricle, suppressed the AV nodal conduction, and increased the effective refractory period of the right ventricle, whereas no significant change was observed in the preload and afterload of the left ventricle, intrinsic sinus nodal automaticity, His-Purkinje-ventricular conduction, and the monophasic action-potential duration of the right ventricle. The cardiovascular effects of esmolol were comparable to those of ONO-1101, except that the preload of the left ventricle was significantly increased, and the ventricular repolarization phase was shortened by 300 microg/kg/min of esmolol infusion. Meanwhile, ONO-1101 as well as esmolol significantly reduced the isoproterenol-induced increase in heart rate and ventricular contraction, but the inhibitory action of ONO-1101 was 6-8 times greater than that of esmolol. These results suggest that the suppressive effects of ONO-1101 on cardiovascular performance are significantly less potent than those of esmolol at equipotent beta-blocking doses.

Pharmacology of N-type Ca2+ channels distributed in cardiovascular system (Review).

Irregular functions in Ca2+ channels are intimately involved in many aspects of cardiovascular diseases. We can obtain a wide variety of L-type Ca2+ channel antagonists to treat hypertension and angina pectoris. Dihydropyridines (DHPs) have, first of all, been extensively developed due to their high selectivity for L-type Ca2+ channel and safety in pharmacological aspects. In contrast, many lines of evidence suggest that clinical efficacy of those DHPs are limited and undesirable effects are sometimes observed because of the specific distribution of L-type Ca2+ channels. As well as the L-type, peripherally distributed N-type Ca2+ channel plays a key role in cardiovascular regulation through autonomic nervous system. Recently, we developed a unique DHP derivative, cilnidipine (FRC8653) which has a dual antagonistic action on both L-type and N-type Ca2+ channels. Our recent studies with this DHP have made it clear that the N-type Ca2+ channel is also a new therapeutic target in cardiovascular diseases. We review the recent advances in pharmacology of the N-type Ca2+ channel and therapeutic implications of their antagonists.