The effects of nicotine (2.5 mg/100 ml), alcohol (25% v/v) and caffeine (30 mg/100 ml base) and their combination (nicotine, 2.5 mg/100 ml; alcohol, 25% v/v; and caffeine, 30 mg/100 ml base) fed in drinking water ad libitum for 21 days were studied on the gastric mucosal damage induced by aspirin, phenylbutazone and reserpine in rats. When given alone, none of them produced any visibly discernible gastric lesions. Their concurrent administration, however, produced some injury to the gastric mucosa which was far less severe than the lesions induced by any of the ulcerogenic drugs used in this study. Pretreatment with nicotine, alcohol and caffeine and their combination resulted in a significant augmentation of gastric lesions produced by aspirin, phenylbutazone and reserpine. These results establish an association between nicotine, alcohol and caffeine in the pathogenesis of gastric ulcers and also implicate them as modifying factors in the genesis of gastric lesions induced by aspirin, phenylbutazone and reserpine.

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The racemate and optical isomers of the C-homobenzomorphans, 1, 4-dimethyl-10-hydroxy-2, 3, 4, 5, 6, 7-hexahydro-1, 6-methano-1H-4-benzazonine, were evaluated in a number of assays sensitive to narcotics of different types. All three C-homobenzomorphans were active in vitro in guinea pig ileum, mouse vas deferens, and rat brain membrane binding assays, but were of low potency. These C-homobenzomorphans showed different profiles of in vivo activity. The (+)-isomer and racemate were active as agonists in the tail-flick assay, whereas the (-)-isomer was inactive. At higher doses, the (-)-isomer and the racemate behaved as antagonists of morphine in the tail-flick assay. All three compounds were active in the phenylquinone test, but naloxone did not block this effect. In addition, all three were potent in the hot-plate test. Neither of the isomers substituted for morphine in dependent rats or monkeys. However, the (+)-isomer precipitated withdrawal in these monkeys. The (-)-isomer produced opioid-like physical dependence in both rats and monkeys. Some of the implications regarding the results with these remarkable homobenzomorphans are discussed.

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¹H NMR spectroscopic studies have been carried out for multidispersed vesicles of DMPC and DOPC in the presence of Eu(NO₃)₃ and anesthetics (tetracaine and lidocaine). ¹H NMR signals of DMPC vesicles disappeared, while those of DOPC did not, in the coexistence of Eu(N0₃)₃ and the anesthetics. An addition of EDTA-Na₄ to this solution regained the signals of DMPC vesicles, implying cancellation of the effect of Eu(III) ions by chelating with EDTA anions. Intervesicular aggregation was proposed as a molecular mechanism responsible for the signal disappearance.

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In order to examine a possible contribution of cyclic AMP to acetylcholine (ACh) release from guinea pig ileum myenteric plexus, effects of adenylate cyclase inhibitors, phosphodiesterase (PDE) inhibitors and dibutyryl cyclic AMP on the spontaneous and the various stimuli-induced ACh release were investigated. A PDE inhibitor, theophylline (1 mM) increased the ACh release induced by nicotine (6.16 μM) significantly. Another PDE inhibitor, 3-isobutyl-1-methylxanthine (IBMX, 1 mM) and dibutyryl cyclic AMP (4 mM) had no effect. The adenylate cyclase inhibitors dithiobisnitrobenzoic acid (DTNB, 1 mM) and alloxan (4 mM) both decreased the nicotine-induced ACh release remarkably. PDE inhibitors increased and adenylate cyclase inhibitors decreased the high-K⁺-induced ACh release. Dibutyryl cyclic AMP brought about a slight but significant increase of the high-K⁺-induced ACh release. All the drugs failed to alter the ACh release induced by electrical field stimulation (EFS) at 10 Hz. Effects of all drugs except dibutyryl cyclic AMP on the spontaneous ACh release were the same as those on the nicotine-induced one. Dibutyryl cyclic AMP decreased it significantly. These results suggest that the cyclic AMP system is involved in the spontaneous, the nicotine-induced and the high-K⁺-induced ACh release and that the EFS-induced ACh release is independent of cyclic AMP.

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The stimulatory effect of forskolin on amylase secretion was studied by pretreating rat parotid tissue with forskolin for 10 min, incubating it in medium without forskolin for 10 min, and then treating it with forskolin again. Pretreatment with 10 μM forskolin for 10 min resulted in increased amylase secretion and enhanced accumulation of cyclic AMP in the tissue during the second incubation with forskolin. In the presence of colchicine or vinblastine, the enhancement in cyclic AMP accumulation during the second incubation with forskolin was prevented, but the increased amylase secretion remained unchanged. The increased amylase secretion was counteracted only in the presence of concanavalin A. On the other hand, increased amylase secretion induced by isoproterenol (IPR) pretreatment was counteracted by colchicine, vinblastine, concanavalin A or strychnine. These data suggest that the total amount of cyclic AMP in the tissue does not have any essential role in the supersensitivity of the amylase secretory response, and that the supersensitivity induced by forskolin differs from that induced by IPR.

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In order to elucidate possible mechanisms of the learning deficit produced by postnatal pretreatment with chlorpromazine (CPZ), changes in catecholamine receptors in the rat brain were investigated. Male neonates of Wistar strain rats were given s.c. 2 mg/kg/day of CPZ for 7 successive days from days 6 to 12 after birth. Effect of the postnatal pretreatment with CPZ on saturation constants for specific bindings of ³H-spiperone, ³H-WB 4101 and ³H-dihydroalprenolol, respectively, in 8 brain regions was investigated at 60 days after birth. Significant decreases in B_max values of ³H-WB 4101 binding sites in the cortex, thalamus, hypothalamus, mid brain and medulla oblongata/pons and decreases in K_d values of the binding sites in thalamus, hypothalamus and mid brain were observed in CPZ-pretreated rats when compared with corresponding B_max and K_d values obtained in saline-pretreated rats. Furthermore, significant decreases in both B_max and K_d values of ³H-DHA binding sites in the thalamus were detected in CPZ-pretreated rats when compared with those obtained in saline-pretreated rats. However, no alterations in ³H-spiperone binding sites in all brain regions were found between CPZ- and saline-pretreated rats. These results suggest that the learning deficit observed in CPZ-pretreated rats may be produced by a functional disorder of catecholaminergic, in particular α₁-noradrenergic neurons in the brain.

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Using the isolated perfused heart preparations of the rat, effects of diltiazem, a calcium antagonist, on the ischemic derangements of the mechanical function and the energy metabolism of the ventricular myocardium were studied. The myocardial tissue levels of creative phosphate (CP), ATP, inorganic phosphate (Pi) and pH were determined with ³¹P-NMR. Global ischemia was induced by cross-clamping of the aortic inflow line for 15 min, which resulted in a fall of CP, ATP and pH and a rise of Pi. The test hearts were perfused with diltiazem-containing solution (10^-7, 10^-6 and 10^-5 M) for 12 min prior to the induction of the global ischemia. A significant dose-related decline of the myocardial mechanical function expressed as (left ventricular pressure)×(heart rate) was observed in diltiazemtreated hearts. In doses above 10^-6 M, diltiazem delayed the onset of the fall of the myocardial CP and pH levels and the rise of Pi induced by ischemia, and there was an excellent correlation between the suppression of the myocardial mechanical function observed before induction of ischemia and the level of the myocardial CP and pH at the initial phase of ischemia, indicating that the improvement of the myocardial energy metabolism was due to the cardiodepressant effects of the compound.

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The effect of ticlopidine on platelet membrane fluidity was investigated using a spin label technique. Ticlopidine, when orally administered to rats, increased both the order parameter and the motion parameter, indicating a decrease in the membrane fluidity of platelets. On the other hand, the order parameter and the motion parameter decreased markedly when the platelets were aggregated by thrombin. Ticlopidine inhibited the thrombin-induced aggregation of platelets and caused a slight increase in order parameter and motion parameter in thrombinaggregated platelets. Judging from sodium dodecyl sulfate polyacrylamide gel electrophoresis, ticlopidine did not modify the electrophoretic pattern of platelet proteins appreciably. Ticlopidine decreased cholesterol/phospholipids molar ratio and increased slightly total amounts of proteins of the platelets. These results indicate that the inhibitory action by ticlopidine was accompanied by changes in membrane fluidity, and these changes were due to a perturbation of the membrane phospholipid core of the platelets by ticlopidine and/or its metabolites.

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Effects of ouabain on a high K-induced contraction and intracellular Na and K contents of the ileal longitudinal muscle preparations isolated from various animal species was compared. In muscles of various animals (monkey, dog, cat, rabbit, guinea-pig, rat and mouse), the high K-induced contraction was inhibited by verapamil (5×10^-8 M) or ouabain (3×10^-6 M), and both the inhibitions were antagonized by an increase in external Ca in a competitive manner. Species differences were shown in the ouabain effect but not in the verapamil one. Regarding the sensitivity to ouabain, the muscles were divided into two groups, that is, the muscle from monkey, rabbit, guinea-pig or dog belongs to the high sensitivity group, and that from cat, rat or mouse belongs to the low one. The order of sensitivities of the muscles to ouabain in the relaxation was consistent with that in Na, K-ATPase inhibition, as reported by Repke et al. (1965). Intracellular Na contents of muscles were increased by an addition of ouabain to the high K solution, and the rate and amount of the accumulation of intracellular Na varied in these muscles. Except for the cat muscle, a high correlation was noted between the ouabain-induced relaxation and the amount of intracellular Na accumulation. However, the regression coefficients were variable: 4.1 in the monkey muscle, 2.2 in the rat one, and about 1 .0 in the others. That is, the monkey muscle showing the high regression coefficient value probably has a high sensitivity to the inhibition of intracellular Na in the high K-induced contraction. In summary, the high K-induced contractions of ileal longitudinal muscle preparations isolated from the various animals species were inhibited by ouabain (10^-6-10^-4 M), in varing degrees. It is suggested that the species difference in the ouabain-induced relaxation is composed of two species differences in the inhibition of Na, K-ATPase in the muscle and the sensitivity of the muscles to the accumulated sodium and that the ouabain-induced relaxation in the ileal muscles is probably induced by an inhibition of accumulated Na to the increased Ca influx by depolarization.

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The venodilating action of nipradilol was investigated by monitoring arterial blood pressure (BP), cardiac output (CO), heart rate (HR) and central venous pressure (CVP) in pithed rats treated with dihydroergotamine (DHE). DHE increased CVP and produced a simultaneous rise in BP and CO without appreciable changes in total peripheral resistance (TPR) and HR, indicating that DHE reduces venous capacity through venoconstriction. Nipradilol caused a fall in CVP, BP and CO without changing the TPR in the DHE-pretreated rat. By comparison, hydralazine reduced BP and TPR without changes in CO. Propranolol produced only a transient decrease in BP and TPR. These results indicate that nipradilol dilates venous capacitance vessels and thereby decreases cardiac filling pressure in animals with high venous tone, whereas hydralazine preferentially dilates resistance vessels.

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Dextran sulfate has an action on aprotinin activity similar to that seen with heparin: preincubation of dextran sulfate with aprotinin enhanced the inhibitory effect of aprotinin on the esterolytic activity of trypsin, but did not change the effect on the proteolytic activity of trypsin or on the esterolytic and proteolytic activities of chymotrypsin. The enhancing effects of heparin and dextran sulfate were not due to increase in the active form of aprotinin which reacts with trypsin, but rather due to a change in the aprotinin molecule which would lead to an increase in aprotinin activity.

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To determine whether or not α-methyladrenaline (MA) is an active metabolite of α-methyldopa, a centrally-acting hypotensive compound, we measured MA in the rat brain using the high-performance liquid chromatographic electrochemical detection method. After five daily treatments of α-methyldopa given twice daily a dose of 40 mg/kg, we found trace amounts of MA in the hypothalamus and C1-C2 area (hypothalamus, 23.7±2.3 picomole/g, n=7; C1-C2 area, 5.4±0.4 picomole/g, n=4), as well as large amounts of α-methylnoradrenaline (MNA) (Hypothalamus, 16.6±0.4 nanomole/g, n=7; C1-C2 area, 7.0±0.2 nanomole/g, n=4). In these brain areas, the amount of endogenous adrenaline was reduced to 10.6% and 16.1% of the control values, respectively. The amounts of MA were only 9.0% and 6.2% of that of endogenous adrenaline in these respective areas whereas MNA was detected at approximately the same level as endogenous noradrenaline. These findings indicate that MA is synthesized from α-methyldopa to a very minute extent in the hypothalamus and C1-C2 area, and a large amount of MNA was synthesized in these areas. These are of interest considering the changes of endogenous adrenaline and noradrenaline. Our results raise doubts about the participation of MA on the main determinant of the central hypotensive effect of α-methyldopa.

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Forskolin (1 to 100 μM), a direct activator of adenylate cyclase, did not have any effect on prostaglandin E₂ and I₂ productions in isolated dog renal arteries. However, forskolin at the lower concentrations (10 and 100 nM) markedly stimulated only prostaglandin E₂ production. 8-Bromo-cyclic AMP (0.5 and 1 mM) failed to stimulate prostaglandin E₂ and I₂ productions. The results suggest that 1) forskolin stimulates only prostaglandin E₂ production, not through the activation of adenylate cyclase and 2) the prostaglandin production system may be independent of the cyclic AMP-generating system in isolated dog renal arteries.

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A new simple and economical plastic Boyden chamber for in vitro assay of leukocytes chemotaxis was devised by the use of a commercially available immunoassay plate. Zymosan-activated rat serum, formly-methionyl-leucylphenylalanine and leukotriene B₄ caused concentration-dependent migration of the leukocytes into the lower chamber. About 50% of the cells loaded in the upper chamber migrated into the lower chamber for 80 min at the optimal concentrations of the three chemoattractants tested.

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Suckling rats were injected with hydrocortisone at 12 and 13 days after birth and were sacrificed for the experiment at 15 days. Alkaline phosphatase in the duodenum was detected as three activity bands on SDS-polyacrylamide gel electrophoresis, while in control rats, the enzyme showed a single band. The electrophoretic pattern in hydrocortisone-treated rats was similar to that observed in adult rats. This result supports the view that the maturation of intestinal alkaline phosphatase is primarily regulated by glucocorticoids.

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Effect of KF4939 on activation of phospholipase C and A₂ was examined by using rabbit platelets prelabelled with [¹⁴C]-arachidonic acid. The results showed that KF4939 inhibited the activation of the two phospholipases, separately. The inhibition of phospholipase C activation is thought to be a possible mechanism of KF4939 to inhibit aggregation and secretion which are independent of the synthesis of cyclooxygenase products such as thromboxane A₂.

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The analgesic mechanism of morphine on the spinal nociceptive transmission was compared in rabbits with the intact and cold-blocked states of the spinal cord. The degree of the suppressive effect of morphine (2 mg/kg) on the bradykinin-induced activity was significantly greater in the intact than in the coldblocked states. Morphine (4 mg/kg) suppressed the nociceptive responses to similar levels in both states. These results suggest that in a small dose, the indirect suppressive action is more important than the direct action. In a larger dose, the suppressive action is probably exerted primarily by the direct spinal action.

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Stressful stimuli, electric footshock (FS), immobilized-water immersion (IW), and cold-water swimming (CWS), produced analgesia and prolonged the pentobarbital hypnosis as well as morphine and clonidine. Naloxone completely antagonized the analgesic effects of morphine and FS and partially that of IW; however, that of clonidine and CWS were not reversed by naloxone. Naloxone eliminated the hypnosis prolonging effect of morphine and FS, but failed to reverse the effect of clonidine, IW and CWS. Differences in the analgesic and hypnosis prolonging effects and also the respective naloxone sensitivity of each drug and stress suggest the diversity of the underlying mechanisms.

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Intracistern al administration of caerulein inhibited the food intake in mice, but the caerulein action was antagonized by benzodiazepines such as chlordiazepoxide, diazepam and flurazepam which were administered intraperitoneally in low doses (0.2 to 2 mg/kg). The antagonism mechanism between caerulein and benzodiazepines remains unclear, but the characteristics of the antagonism were similar to those which had been observed with cholecystokinin and benzodiazepines.

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