The effects of KB-2796, a new calcium antagonist with a diphenylpiperazine moiety, on renal hemodynamics and urine formation were investigated in anesthetized dogs. Intravenous infusion of KB-2796 (10, 30, and 100 μg/kg/min) decreased mean blood pressure (MBP) and renal vascular resistance (RVR) in a dose-dependent manner, but did not change renal blood flow (RBF). At the highest dose, glomerular filtration rate (GFR) and urine flow (UF) -tended to decrease. Nicardipine (0.1, 0.3, and 1 μg/kg/min) also dose-dependently decreased MBP, RVR, GFR, and UF. When KB-2796 was infused into the renal artery at lower doses of 3 and 10 μg/kg/min, UF and urinary excretion of electrolytes increased without a significant change in RBF and GFR. Intrarenal infusion of KB-2796 at 30 μg/kg/min and nicardipine at 0.3 μg/kg/min produced a significant increase in GFR, RBF, UF, urinary excretion of electrolytes, and renin secretion rate. These results suggest that KB-2796 administered intrarenally exerts a diuretic action via tubular effects and the alteration of renal hemodynamics. However, its diuretic action might be masked by diminished urine formation via a reflex activation of the sympathetic nerves and/or via a reduction of renal perfusion pressure when it is administered systemically.

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The anti-hypotensive effects of M6434 were evaluated and compared with those of other orally active sympathomimetics in rats. Oral administration of M6434 (0.5-2.0 mg/kg) and midodrine (1.0-5.0 mg/kg) also produced a dose-related increase in mean arterial pressure in normotensive rats. The pressor effect of M6434 was about 4 times more potent than that of midodrine. Both M6434 and midodrine caused a dose-dependent decrease in heart rate. The pressor effect of M6434 (1.0 mg/kg) did not diminish after its repeated administration for 7 days. The pretreatment with M6434 (0.5-1.0 mg/kg) and midodrine (2.0-5.0 mg/kg) improved the orthostatic index in the experimental model of postural hypotension in rats. The effect of M6434 on postural hypotension was about 5 times more potent than that of midodrine. Intravenously injected M6434 (3-300 μg/kg) produced a dose-dependent increase in the blood pressure of pithed rats. These results suggest that M6434 possesses a potent anti-hypotensive activity which is superior to that of midodrine, and M6434 may be useful in the treatment of essential and postural hypotension.

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Effects of mucosal application of capsaicin on alkaline secretion were examined in the stomachs of anesthetized rats and compared with those in the duodenum. The stomach (acid secretion was inhibited by omeprazole given i.p.) or the duodenum was perfused with saline (pH 4.5); both the pH of the perfusate and transmucosal potential difference (PD) were continuously monitored; and the HCO₃^- output was determined by the pH change. Under these conditions, the mucosal application of capsaicin (0.3-6 mg/ml for 30 min) caused significantly increased pH and HCO₃^- output in a concentration-related manner in both tissues, while PD increased in the duodenum and decreased in the stomach. The HCO₃^- stimulatory action of capsaicin was markedly attenuated by sensory deafferentation, significantly mitigated by prior administration of indomethacin, and exhibited a marked tachyphylaxis after the repeated exposure at a high concentration (6 mg/ml). None of these treatments had any effect on the pH, PD and HCO₃^- responses induced by prostaglandin E₂ (300 μg/kg, i.v.) in these tissues. These results indicate that mucosal application of capsaicin increased the gastroduodenal HCO₃^- output by stimulation of capsaicin-sensitive sensory neurons. This action may be in part mediated by endogenous prostaglandins.

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The present study was conducted to investigate the antinephritic effects of berberine and coptisine, which are contained in Coptidis rhizoma, on original-type anti-GBM nephritis in rats. Berberine and coptisine at the doses of 0.5, 1.0 and 5.0 mg/kg/day, i.p. were effective in inhibiting urinary protein excretion, elevation of serum cholesterol and creatinine contents as well as glomerular histopathological changes. In addition, berberine at 20 mg/kg/day, p.o. also inhibited urinary protein excretion throughout the experimental periods. Berberine and coptisine inhibited platelet aggregation in both in vitro and in vivo assays, and berberine inhibited the decline of renal blood flow. Although berberine inhibited an increase in thromboxane B₂ formation, it increased the formation of 6-keto-prostaglandin F_1α in platelets and isolated glomeruli. These results indicate that the antinephritic effects of berberine and coptisine may be partly due to antiplatelet action and improved renal hemodynamics via changing prostanoid synthesis.

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Effects of the water-soluble extract of Ganoderma tsugae mycelium (GT), its alcohol-insoluble subfraction (GTI), and its alcohol-soluble subfraction (GTS) on splenic natural killer (NK) cell activity and serum interferon (IFN) production were assessed in mice. Intraperitoneal administration of GT (4-200 mg/kg) or GTI (1-50 mg/kg), but not GTS, augmented the NK cytotoxic activity in a dose-dependent manner in C3H/HeN mice. This augmentation of splenic NK cytolytic activity was not mouse-strain-dependent. The serum IFN titers of mice were also elevated after i.p.-doses of GTI. The GTI-induced serum IFN was reduced by either IFN-(α + β) antiserum or IFN-γ monoclonal anti-body in vitro. The treatment with antiserum neutralizing IFN-(α + β) resulted in a 70% reduction of GTI-induced IFN, while monoclonal antibody against mouse IFN-γ, moderately neutralized the GTI-induced IFN (50%). These results demonstrated that both the splenic NK activity and serum IFN [IFN-(α + β) and IFN-γ] titers are elevated by Ganoderma tsugae mycelium extracts in mice.

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We investigated the effects of semotiadil (SD-3211), a novel calcium antagonist, on blood pressure and the atrioventricular (AV) conduction time and functional refractory period (FRP) of the AV conduction system (AV conductivity) in anesthetized open-chest dogs. The heart was electrically stimulated at a constant rate. In dogs with an intact nerve supply to the heart, i.v.-injections of semotiadil (0.03 to 0.3 mg/kg) produced a fall of blood pressure in a dose-dependent manner. AV conduction time and FRP were prolonged by rather higher doses (0.3 mg/kg), and second-degree AV block occurred only with the highest dose (1 mg/kg). In dogs with the nerve supply to the heart interrupted, the vasodepressor effects and suppressant effects of semotiadil on AV conductivity were slightly enhanced. The suppressant effects on AV conductivity became marked as pacing rates were increased. These results suggest that semotiadil at appropriate doses produces a vasodepressor effect without affecting AV conductivity even in the heart deprived of nervous control, e.g., the heart with β-adrenoceptors blocked. The frequency-dependent suppressant effect on FRP of semotiadil is also noteworthy in the treatment of reentrant supraventricular tachycardia that involves the AV node.

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Using a fluorescent Ca²⁺-sensitive dye, fura-2, and photometric fluorescence microscopy, we measured changes in cytosolic Ca²⁺ concentration ([Ca²⁺]_i) in cultured human endothelial cells and studied the effect of dilazep on [Ca²⁺]_i elevation induced by histamine. Histamine (1 μM) caused a rapid transient peak in the average [Ca²⁺]_i of a group of cells (approximately 10² cells), followed by a decrease to a sustained elevation. Dilazep as well as diltiazem (1.0 to 100 μM) concentration-dependently inhibited the latter sustained elevation, which was eliminated by removal of extracellular Ca²⁺, while the initial transient response was not changed by dilazep at concentrations up to 100 μM. The IC₅₀ values of dilazep and diltiazem were 16 and 58 μM, respectively. The patterns of the [Ca²⁺]_i elevation responses to histamine were variable among individual cells. Some single cells showed a transient peak and a sustained elevation as observed in a group of cells. Some single cells caused a repetitive spikelike elevation of [Ca²⁺]_i. Dilazep lowered the sustained elevation to the resting level and in some single cells, changed the sustained elevation to the spikelike elevation. The frequency of the spikelike [Ca_i]_i elevation was also decreased by dilazep. Decrease in extracellular [Ca²⁺] showed the same pattern of inhibitory actions as dilazep did. These results indicate that dilazep inhibits the extracellular Ca²⁺ influx in endothelial cells.

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The intracellular cation contents were determined in isolated perfused rat heart using cobaltic EDTA as a marker of the extracellular space. In hearts in which Na⁺ accumulation was induced with monensin, a Na⁺ ionophore, during 20 min-ischemia which otherwise did not result in accumulation of Na⁺, the levels of Na⁺ and Ca²⁺ were significantly higher after reperfusion with a significant decrease in K⁺. While the recovery of the cardiac mechanical function (CMF) was complete after reperfusion in control hearts, the recovery was incomplete in monensin-hearts. Dichlorobenzamil (DCB), the most specific inhibitor of Na⁺-Ca²⁺ exchanger, infused for 10 min before induction of ischemia in a dose of 10^-5 M, which produced a definite suppression of CMF (over 80%), inhibited the accumulation of Ca²⁺ and Na⁺ and the loss of K⁺ and ATP after 40 min-ischemia and reperfusion. The same dose of DCB given for 3 min before induction of ischemia and after reperfusion, which produced a less than 20% inhibition of CMF, failed to prevent the Ca²⁺ accumulation after 40 min-ischemia and reperfusion. These findings are at variance with the idea that the accumulation of Na⁺ during ischemia and the consequent augmented operation of Na⁺-Ca²⁺ exchange is responsible for accumulation of Ca²⁺ after reperfusion.

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Active cutaneous anaphylaxis (ACA) was studied in the ear of female BALB/c mice. Mice were immunized with ovalbumin in the presence of aluminium hydroxide gel or complete Freund''s adjuvant (CFA). Two weeks after the immunization, ACA was elicited in the mouse ear by injecting 10 μl of antigen solution intradermally into the ear lobe. ACA was assessed by the amount of extravasated dye, which was given intravenously just after the antigen injection. Antiallergic drugs (tranilast, ketotifen and azelastine), antihistamines (chlorpheniramine, diphenhydramine and mequitazine), β-stimulants (isoproterenol and salbutamol), theophylline and glucocorticoids (hydrocortisone, prednisolone and dexamethasone) inhibited the reaction significantly. These drugs inhibited both ACA in mice immunized with alum-precipitated antigen and ACA in mice injected with CFA-emulsified antigen similarly. ACA in the mouse ear might be a useful tool for studying drugs for allergy.

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We have previously found that the administration-time-dependent change in the effects of furosemide, a loop diuretic agent, is observed in normal rats. The present study was undertaken to examine whether an alteration in this phenomenon occurs in rats with DOCA-saline hypertension. Unilateral nephrectomized rats were divided into three groups. The first group (DOCA-saline) received a 50 mg DOCA tablet intraperitoneally and drank 1% NaCl solution. The other two groups were given sham operations. A 1% NaCl solution was given as drinking water to the second group (control-saline), while tap water was given to the third group (control-water). Furosemide (30 mg/kg) was given orally to each group at 12 a.m. or 12 p.m. Urine was collected for 8 hours after the agent, and urinary excretion of sodium and furosemide were determined. Urine volume and urinary excretion of sodium and furosemide following the agent were significantly greater at 12 a.m. than at 12 p.m. in the control-water and control-saline groups. However, the administration-time-dependent changes in these parameters disappeared in the DOCA-saline rats. These results suggest that the mode of the administration-time-dependent changes in the effects of furosemide is altered in the DOCA-saline hypertensive rats.

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Specific [³H]-substance P binding was saturable and of high affinity (K_D = 2.5 nM) with a B_max of 725 fmol/mg protein in the isolated rabbit iris sphincter muscle. The competition for [³H]-substance P binding was in the order of eledoisin > substance P > kassinin > neurokinin B > neurokinin A > physalaemin. In the same preparation, neurokinin A, as well as substance P induced a concentration-related accumulation of [³H]-inositol phosphates (IPs), and the maximum increase was about 200% of the control at 10^-4 M. [D-Arg¹, D-Trp^{7, 9}, Leu¹¹]-substance P (SP) and [D-Pro², D-Trp^{7, 9}]-SP (10^-3 M) inhibited substance P or neurokinin A (10^-4 M)-induced phosphatidylinositol 4, 5-bisphosphate (PIP₂) hydrolysis significantly. [D-Arg¹, D-Pro², D-Trp^{7, 9}, Leu¹¹]-SP (10^-3 M) also inhibited neurokinin A (10^-4 M)-induced PIP₂ hydrolysis significantly. Neurokinin A and substance P produced concentration-related contractions in normal Ca²⁺-containing medium. The contractile response was weaker in Ca²⁺-free medium, and there was no response in 0.2 mM EGTA medium. In Ca²⁺-free medium, the basal level of [³H]-IPs accumulation was smaller than that in normal medium, and neurokinin A and substance P significantly increased PIP2 hydrolysis. In the 0.2 mM EGTA containing medium, neurokinin A and substance P did not stimulate the PIP₂ hydrolysis. These results suggest that in the rabbit iris sphincter muscle, there are tachykinin receptors linking to PIP₂ hydorolysis and Ca²⁺ mobilization and that these mechanisms underlie the mechanism for the neurokinin A-induced contractile response, as well as the substance P-induced one.

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The involvement of visceral afferent fibers and 5-HT₃ receptors in the emesis induced by cisplatin was studied in beagle dogs. The emesis induced by cisplatin (3 mg/kg, i.v.) was inhibited by the intravenous administration of ICS205930 (2 × 0.01 or 2 × 0.1 mg/kg) and MDL72222 (2 × 0.5 mg/kg), 5-HT₃ receptor antagonists, but not by the intravenous administration of metoclopramide (2 × 0.5 mg/kg), a dopamine D₂ receptor antagonist. The cisplatin-induced emesis was also suppressed by the intravenous administration of para-chlorophenylalanine (300 mg/kg/day for 3 days), an inhibitor of 5-HT synthesis. On the other hand, the administration of ICS205930 into the IVth ventricle (2 × 0.01 mg/animal) had no effects on the cisplatin-induced emesis. The cisplatin-induced emesis was completely inhibited by abdominal vagotomy and splanchnicectomy, but not by splanchnicectomy alone. On the contrary, the emesis induced by apomorphine was suppressed by the intravenous (0.1 mg/kg) or intracerebroventricular (0.05 mg/animal) administration of metoclopramide, but not by visceral nerve section. These results strongly suggest that cisplatin evokes emesis mainly by acting on the vagal afferent terminals through the release of 5-HT and that peripheral 5-HT₃ receptors are involved in this action.

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Effects of 9-[(4-acetyl-3-hydroxy-2-n-propylphenoxy)methyl]-3-(1H-tetrazol-5-yl)-4H-pyrido [1, 2-a]pyrimidin-4-one (AS-35) on the resting tonus or contractions induced by agonists, such as leukotriene (LT) D₄ and specific antigen of isolated guinea pig tracheas or human bronchi, and the in vitro anaphylactic release of histamine and LTs from human lung fragments were investigated and compared with the effects of FPL 55712 and disodium cromoglycate. AS-35 as well as FPL 55712 did not affect the contractions induced by acetylcholine and histamine of the isolated guinea pig trachea. However, the compound at relatively low concentrations obviously inhibited contractions induced by LTD₄, and the antagonistic activity was stronger than that of FPL 55712. Treatment of the isolated human bronchus with AS-35 tended to induce the inhibition of both LTD_4^- and antigen-induced contractions and the relaxation of the resting tonus in a concentration-dependent manner. The inhibitory potency at 10^-6 g/ml was slightly stronger than that of FPL 55712, but this was not statistically significant. The anaphylactic release of histamine and LTs from the lung fragments appeared to be inhibited by the treatment with AS-35 5 min prior to the antigen challenge. From these results, it is suggested that AS-35 is effective against allergic asthma through antagonism towards peptide-LTs released anaphylactically in addition to inhibition of the chemical mediator release.

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Recombinant human tumor necrosis factor-β (rhTNF-β) may be encapsulated with high efficiency in phosphatidylcholine and distearoylphosphatidylcholine liposomes, with entrapment values of 93.4% and 92.3%, respectively, by first entrapping the substance in multilamellar vesicles using a high solute-to-phospholipid ratio followed by freeze-drying and then rehydration. The entrapped cytokine retains potent cytotoxic activity on L929 cells in vitro, causing 100% cytotoxicity, equal to that of free rhTNF-β at a concentration of about 5 × 10^-8 g/ml.

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We have investigated the effect of endothelin (ET)-1, ET-3 and ET-(16-21) on isolated and perfused rat kidney (IPK). ET-1 and ET-3 produced a similar dose-dependent increase in perfusion pressure of IPK, while ET-(16-21) was completely inactive. The ET-1 effects were greater in spontaneously hypertensive rats (SHR) as compared to normotensive rats (WKYR), whereas the ET-3 effects were greater in the SHR group only at the lowest doses. The pressure response of IPK induced by ET-1 was partially modified by prior application of the nitric oxide synthetase inhibitor L-nitroarginine in both WKYR and SHR.

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Pretreatment with MK-801, a non-competitive N-methyl-D-aspartate (NMDA) antagonist, failed to protect the vagal component of reflex bradycardia from 5-min global cerebral ischemia in dogs under pentobarbital anesthesia. On the other hand, MK-801 completely prevented the development of the post-ischemic cerebral hypoperfusion without affecting the cerebral blood flow in sham-operated animals. The results suggest that NMDA receptors may participate in the development of the secondary disturbance of the cerebral circulation, but are not involved in the post-ischemic dysfunction of the baroreflex system.

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The effects of nebracetam were investigated on N-methyl-D-aspartate (NMDA) receptor- and voltage-operated Ca²⁺ channels (VOCC)-mediated neural dysfunction by directly monitoring the real-time dynamics of dopamine released from rat striatal slices. Nebracetam (10^-5 and 10^-4 M) completely protected against striatal dopaminergic impairment induced by L-glutamate and NMDA, respectively. BAY K-8644-evoked striatal dysfunction was not blocked by nebracetam (10^-4 M). Therefore, nebracetam seems to produce a neuroprotective action by interacting, at least in part, with NMDA receptor-operated Ca²⁺ channels.

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Ketotifen, a histamine H₁-receptor antagonist and mast cell stabilizer, significantly protected the rat gastric mucosa against lesions induced by necrotizing agents, histamine or compound 48/80. The agent significantly inhibited the basal gastric acid secretion, but had little or no effect on the histamine-stimulated secretion. The mucosal protective effect was observed even at a dose that had little or no effect on gastric acid secretion, suggesting that ketotifen exhibits so-called cytoprotective activity.

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The inhibitory effect of manidipine, a long acting calcium channel blocker, on vascular smooth muscle cell proliferation was investigated in spontaneously diabetic GK rats with balloon catheter-induced denudation of the carotid artery. Treatment with manidipine at doses of 4.6 and 15.1 mg/kg/day inhibited thickening of the neo-intima in the balloon catheter-injured artery without any effect on blood pressure and lowered the ratio of intima to wall areas and wall to total vascular areas in a dose-dependent fashion. These results suggest that manidipine inhibits an abnormal proliferation of the intima in the carotid artery of spontaneously diabetic rats.

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The influences of protein kinase inhibitors, K-252a and staurosporine, on the neuro-trophic effects of epidermal growth factor (EGF) were investigated in dissociated cell cultures of the hippocampus and cerebellum of fetal rats. Addition of 1 ng/ml EGF enhanced the survival of cultured neurons of both brain regions. Both K-252a (10-200 nM) and staurosporine (1-100 nM) blocked the survival-promoting effects of EGF in a concentration-dependent manner. These results suggest that activation of protein kinase(s) is involved in the neurotrophic effects of EGF.

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Dibutyryl cyclic AMP and forskolin inhibited the contraction induced by norepinephrine (NE) more strongly than the high K⁺-induced contraction in isolated rat aorta. These inhibitors inhibited the ⁴⁵Ca²⁺ influx stimulated by NE but not that by high K⁺, and they inhibited NE-induced inositol monophosphate accumulation. These results suggest that cAMP inhibits NE-induced contraction, at least partly, by inhibiting the α-adrenoceptor-mediated signal transduction and high K⁺-induced contraction by decreasing Ca²⁺ sensitivity but not Ca²⁺ influx.

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