The pharmacokinetic and pharmacodynamic interactions between hydralazine (HP) and furosemide or trimethazidine were determined following single i.v. and repeated (7 d) oral administrations in rats. Both furosemide and trimethazidine caused a significant descrease in the level of plasma protein binding of HP in vivo after i.v. administration. However, in vitro there was no effect on binding. Coadministration of HP and furosemide at lower doses (1.67 mg/kg, i.v. and 5 mg/kg, oral) reduced the hypotensive effect, accompanying the enhanced elimination of HP from plasma after a single i.v. and repeated oral treatment when compared to the result obtained with HP alone. The elimination of HP accelerated by the lower doses of furosemide may be probably due to the increase in renal clearance by the diuretic effect of furosemide. 0n the contrary, a high dose (10 mg/kg, i.v.) of furosemide temporarily strengthened the hypotensive effect, probably due to the additional hypotensive action of furosemide itself. Trimethazidine (0.75 and 3.75 mg/kg) gave a small increase in the hypotensive effect of HP in spite of the partially enhanced clearance of HP. The pharmacodynamic analysis showed that the hypotensive effect of HP depended upon the plasma HP concentration in each treatment, although the response curves of HP were partly altered by the combined drugs. The present study also suggests a validity of coadministration of HP and diuretics for the therapy of hypertension and heart failure.

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The effect of temperature on the transfer and the tissue uptake of sulfanilamide and aminopropyron, an aminopyrine derivative, was investigated using the everted and the non-everted sacs of rat intestine. The M (mucosa) to S (serosa) transfer of sulfanilamide was slightly faster than reverse S-to-M in the ileum at the temperatures studied. Decreased transfer and tissue uptake of sulfanilamide with decreasing temperature were observed using both ileal everted and non-everted sacs. On the contrary, the M-to-S transfer of aminopropyron was slower than the S-to-M transfer in the ileum. The tissue uptake of aminopropyron was almost constant at any temperature in the ileal non-everted sac experiments, while a decreased transfer of aminopropyron was observed with a decrease in temperature. Similar results, like aminopropyron in the ileum, were obtained in the experiments of aminopropyron and sulfanilamide using the colonic sacs. It is concluded that a close relationship may exist between the directional superiority in the transfer and the temperature independency of the tissue uptake

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Hepatic transport system of benzylpenicillin was characterized by using freshly prepared rat hepatocytes. Uptake of benzylpenicillin and cefpiramide did not require the presence of sodium ion in the incubation medium. No influence of several kinds of amino acids (leucine, histidine, phenylalanine, valine, alanine, glutamic acid and glycine) and peptides (prolyl-leucine, glycyl-glycine, glycyl-sarcosine, glycyl-leucine and γ-glutamyl-cysteinylglycine) was observed for benzylpenicillin uptake into hepatocytes. Taurocholic acid and cholic acid significantly inhibited benzylpenicillin uptake. The kinetic study revealed that taurocholic acid inhibited benzylpenicillin uptake in a noncompetitive fashion. A similar effect of benzylpenicillin on taurocholic acid uptake was observed, suggesting that the affinity site of the hepatic transport carrier of benzylpenicillin is distinct from that of taurocholic acid. It is noteworthy that p-aminohippuric acid and p-acetylaminohippuric acid did not inhibit benzylpenicillin uptake. In contrast to the mutual inhibition behavior of benzylpenicillin and taurocholic acid, benzylpenicillin is fully and competitively inhibited by the simultaneous addition of probenecid. The inhibition constant K_i value of probenecid was calculated to be 0.322 mM. The uptake of probenecid was also significantly inhibited by benzylpenicillin. It is postulated that the affinity site of benzylpenicillin transport carrier is the same as that of probenecid and that the whole process of the benzylpenicillin transport system is common, at least in part, to the probenecid transport process in the liver.

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The hypersensitivity of the neuromuscular junctions of diabetic mice to succinyl-choline (SuCh), but not to d-tubocurarine (d-TC), was investigated using a cross culture preparation of diabetic skeletal muscle or spinal cord extract with normal tissues. Whether the hypersensitivity is due to the muscle cells themselves was examined using adult muscle of diabetic KK-CA^y, prediabetic KK-CA^y and normal ddY mice cocultured with embryonic spinal cord of normal ddY mice. The cultured neuromuscular junctions between diabetic KK-CA^y muscle and normal ddY spinal cord was hypersensitive to SuCh, but not to d-TC. In contrast, such junctions between prediabetic KK-CA^y muscle and normal ddY spinal cord were not hypersensitive to either drug. The involvement of neuronal factors in hypersensitivity to SuCh in diabetic KK-CA^y neuromuscular junctions was examined using adult spinal cord extract (SCE) from diabetic KK-CA^y and from normal ddY mice. We followed the time course of change in sensitivity of the acetylcholine (ACh) receptors in normal ddY embryonic myotubes to SuCh and d-TC. Both diabetic SCE and normal SCE reduced the sensitivity of myotubes to ACh ; the reduction of ACh potential amplitudes by the former was less than that by the latter. Myotubes cultured with diabetic SCE was hypersensitive to both 1.51 μM SuCh and 0.134 μM d-TC. These results suggest that the hypersensitivity of the neuromuscular junctions in diabetic KK-CA^y mice to SuCh but not to d-TC is mainly attributable to the diabetic muscle cells. themselves.

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The effects of cannabidiol (CBD) and Δ⁹-tetrahydrocannabinol (Δ⁹-THC) on the synthesis and degradation of hepatic microsomal cytochrome P-450 were studied in mice. Cannabinoids used (10, 50 and 100 mg/kg, i.p.) did not affect δ-aminolevulinic acid synthetase activity in the liver. Δ⁹-THC-treatment (10, 50 and 100 mg/kg, i.p. ) markedly stimulated heme oxygenase activity in hepatic 18000 ×g supernatant fractions in a dose-dependent manner, whereas CBD-treatment was without effect. In vitro experiments, CBD and Δ⁹-THC (40 to 160μM) markedly inhibited nicotinamide adenine dinucleotide phosphate (NADPH)-induced lipid peroxidation in hepatic microsomes. When CBD was incubated with the hepatic microsomes in the presence of an NADPH-generating system, cytochrome P-450 content decreased significantly. However, Δ⁹-THC showed no effects in similar experiments. The rate of decrease in the cytochrome P-450 content using CBD (160μM) was 0.212 nmol/mg protein/20 min in microsomes from control mice. This value increased significantly in microsomes from phenobarbital-treated mice (0.792 nmol/mg protein/20 min) but not in those from 3-methylcholanthrene-treated mice (0.190 nmol/mg protein/20 min). The metabolic rate (per nmol cytochrome P-450) of CBD was also increased significantly by phenobarbital-treatment but not by 3-methylcholanthrene-treatment. These results suggest that CBD metabolites rather than CBD itself, play some role in the decreasing effect on cytochrome P-450 content in the hepatic microsomes in vitro, and that the microsomal formation of reactive metabolite of CBD is increased by phenobarbital-treatment.

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Commercially available human serum immunoglobulin G (IgG, native IgG) was separated into two fractions (Fr.I and II) using a diethylaminoethyl cellulose column. Heavy and light chains containing fractions were obtained from these two fractions after carboxamide-methylation. Thus, these fractions were subjected to an anti-inflammatory screening procedure and were shown to have a potent inhibitory activity against rat carrageenin induced paw edema, while no effect was observed in native IgG, Fr.I or II. The reduction and alkylation of the interchain disulfide bonds were essential to induce the anti-inflammatory activity. The anti-inflammatory activity of alkylated heavy and light chains of Fr.I (Fr.I-H and I-L) was also noted in subacute inflammation caused by the felt pellet and croton oil granuloma methods. Moreover, strong membrane stabilizing activities of Fr.I-H and I-L were demonstrated in vitro using rat red blood cell membrane and liver lysosomal membrane.

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C57BL/6 mice were immunized with cauda epididymal sperm from syngenic mice. A monoclonal antibody (TSC4) was obtained using a hybridization method with myeloma (P3U1) cells. The antibody was examined for its reactivity to sperm from different regions of the reproductive tract of male mice. The antigen was recognized only when the sperm reached the corpus epididymis. The area of antigen present on the sperm membrane was topographically restricted to the anterior part of sperm head. The antigen remained on the sperm after washing with phosphate buffered saline, disappearing, however, when sperm were capacitated

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The in vitro anti-tumor activity (inhibition of human lymphoblastic leukemia cells) of some adriamycin analogues is found to be significantly correlated with the van Waals volume (V_w) of the substituents. Activity is also found to be well correlated with first-order valence molecular connectivity index (¹X^v) but no correlation is found to exist between it and the hydrophobic parameter, log P (P : octanol-water partition coefficient). On the basis of these findings, it is suggested that the activity would be affected by the steric influence and to some extent by the electronic character of the substituents. From the correlating equations, it is observed that the size of C-7 glycoside ring and that of NHR₂ group at its third position would greatly affect the activity. The size of C-14-R₁ however, is not found to have much effect on the activity.

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The effects of tryptamine (TRM) on behavior were investigated in mice. TRM at a dose of 50 mg/kg i.p. induced an inhibition of locomotor activity and, at doses ranging from 150 to 300 mg/kg, induced peculiar behaviors such as head twitch, head weaving, forepaw treading, hindlimb abduction and Straub tail. These behavioral effects were continuous, although TRM rapidly disappeared from the brain. Methysergide, a 5-hydroxytrypt-amine(5-HT) receptor antagonist, completely abolished TRM-induced excitatory behaviors and p-chlorophenylalanine, a 5-HT depleter, significantly inhibited the behaviors. Our results show that TRM induced both the depression and excitation in the behavior of mice depending on the dosage and TRM-induced excitatory behaviors may be attributed to both its direct stimulation of 5-HT receptors and facilitation of 5-HT release.

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Mice exhibited a marked suppression of motility (conditioned suppression) when placed in the same environment in which they had previously received an electric footshock. Furthermore, chronic morphine (mu agonist)-pretreated mice, as well as chronic vehicle-pretreated mice, exhibited the conditioned suppression but chronic ethylketocyclazocine (kappa agonist)-and pentazocine (kappa agonist)-pretreated mice did not. On the other hand, in the synaptic membranes of the chronic vehicle- and morphine-pretreated mice showing conditioned suppression, the specific binding of [³H]phencyclidine (sigma agonist) and [³H]naloxone (mu antagonist) significantly increased, while the specific binding of [³H]ethylketocyclazocine did not change compared to those of the corresponding control groups. However, in the chronic pentazocine- and ethylketocyclazocine-pretreated groups showing non-conditioned suppression, the specific binding of [³H]phencyclidine and [³H]naloxone were not altered. Moreover, a decrease of [³H]ethylketocyclazocine binding was observed in the chronic pentazocine-pretreated group. These results suggest that the binding function of different opioid receptor subtypes may be altered differently by stress, and that the kappa receptor may be important for the conditioned suppression of motility in mice.

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The binding of cefazolin to rat sera has been studied as a function of age. A significant difference was observed in the cefazolin binding to serum protein among 1-, 2-, 3-, 5-, 7-, 50- and 100-week-old rats. There was a good correlation between the dissociation constants of cefazolin binding and the molar ratio of free fatty acid to albumin concentration in sera. This suggests that both changes of concentration of albumin and free fatty acid, which could be a major endogenous inhibitor of cefazolin binding, play an important role in the age-related changes of the serum protein binding. Removal of free fatty acid in 1- and 2- week-old rat sera showed marked increases of the cefazolin binding. On the contrary, addition of oleic acid to 7-week-old rat serum produced significant reduction of cefazolin binding to rat serum protein. Accordingly, free fatty acid could effectively inhibit the cefazolin binding in the physiological concentration range with increasing age, and the age-related changes of cefazolin binding to rat serum protein appear to be due to the fluctuation of the molar ratios of free fatty acid to albumin concentration in sera.

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Morphine induced-reduction in response to a repetitive electrical stimulation of the tail was measured in acute rats and rats chronically treated with haloperidol (1 mg/kg/d, for 7 d) following pretreatment with apomorphine. In acute experiments, a significant enhancement of the anti-struggling action of morphine was produced by haloperidol (1mg/kg, i.p.). Low does of apomorphine (30-480 μg/kg, i.p.) had no influence on the suppressing action of morphine on the struggling response induced by the tail stimulation. Following chronic treatment with haloperidol, the inhibitory action of morphine on the tail stimulation-induced struggling response was dose-dependently inhibited by very low doses of apomorphine (60-480 μg/kg, i.p.). A significant increase in 3, 4-dihydroxyphenylacetic acid (DOPAC) levels was observed after administration of haloperidol or morphine in acute rats, whereas no change in DOPAC levels was found after administration of morphine or apomorphine in chronically haloperidol-treated rats. In these animals, basal striatal DOPAC levels were significantly decreased compared with those of vehicle-treated animals controls. The present results suggest that in rats treated chronically with haloperidol, the suppressive action of a low dose of apomorphine on morphine analgesia is due to an in-creased sensitivity of postsynaptic dopaminergic receptors to apomorphine.

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As a first step to elucidate the disposition of traditional Chinese formulations which contain licorice, the disposition of plain licorice was investigated in humans. Glycyrrhetic acid (GLA) was measured by an enzyme immuno-antibody technique. Glycyrrhetic glycosides (GLA-GS), such as glycyrrhizin, were measured after acid hydrolysis to GLA by the enzyme immuno-antibody assay. Five normal subjects were orally administered a decoction of licorice containing 133 mg of glycyrrhizin. It was found that the time required for maximum serum concentration of GLA-GS was less than 4 h after the administration. Although there were large individual differences, it was found that GLA-GS was eliminated from the blood for the most part within 72 h. On the other hand, GLA reached maximum serum concentration at about 24 h after administration and in two of the five cases it was still detected in the blood even after 96 h. Urinary excretion of GLA was about 2% of the total dose of glycyrrhizin administered This suggested that there were great differences among the subjects in the absorption and urinary excretion of GLA-GS. The serum GLA levels in two clinical cases who presented pseudoaldosteronism by licorice containing formulations were as high as 70-80 ng/ml, with GLA-GS levels being very low. This fact suggests that pseudoaldosteronism develops in association with GLA rather than with GLA-GS.

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Mouse ceruloplasmin, the level of which in serum increases on administration of antitumor polysaccharides, was shown to have enhancing effects on the antibody production of mouse spleen cells toward sheep red blood cells and restorative effects on the suppressed mixed lymphocyte reaction of spleen cells of tumor-bearing mice. The proliferation of interleukin-2 dependent cytotoxic T cells and the suppressed concanavalin A response of the tumor bearing mice spleen cells were also enhanced by this serum glycoprotein, weakly but reproducibly. Furthermore, this serum glycoprotein was found to enhance glucose consumption and interleukin-1 production and cytotoxic activities of mouse peritoneal macrophages. These results suggest that mouse ceruloplasmin plays some roles in the natural resistance surveillance against tumors.

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The acetohexamide reducing activity of cytosol of rabbit heart was compared with that of rabbit liver or kidney. The heart exhibited an approximately 2-fold higher activity than either the liver or kidney. Both aldehyde and ketone reductases may contribute to the reduction of acetohexamide by cytosol of rabbit heart. It is noteworthy that the heart is an important organ reducing acetohexamide.

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Intraventricular injection of histamine (Hi) significantly prolonged thiopental sleeping time at doses of 0.5μg or larger. Both 1-methylHi and imidazole-4-acetic acid, howere, did not affect thiopental narcosis. Pretreatment with α-fluoromethylhistidine diminished the effect of Hi, while histidine, metoprine and quinacrine prolonged thiopental narcosis. Injection with 2-methylHi did not affect thiopental sleeping time, while as in the case of Hi, 4-methylHi augmented the thiopental effect. In addition, H₂-receptor blocking agents such as cimetidine, ranitidine and famotidine clearly antagonized Hi-induced prolongation of thiopental narcosis, while pyrilamine and chlorpheniramine had no effect. These results indicate that Hi-induced prolongation of thiopental narcosis appears to be exerted via H₂ receptors and is, in some way, related to the Hi content in the brain.

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