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Biomedical subjects

M Inagaki

Publications and source records attributed to M Inagaki.

At least 397 records · Page 22Linked to original sources
PubMed1985

Relaxation of vascular smooth muscle by HA-1004, an inhibitor of cyclic nucleotide-dependent protein kinase.

A newly synthesized compound, N-(2-guanidinoethyl)-5-isoquinolinesulfonamide (HA-1004), was shown to be a potent inhibitor of two cyclic nucleotide-dependent protein kinases, cyclic GMP-dependent protein kinase and cyclic AMP-dependent protein kinase and the Ki values were 1.4 and 2.3 microM, respectively. HA-1004 relaxed rabbit aortic strips contracted by various agonists and with similar ED50 values. Phenotolamine, propranolol and atropine did not affect this HA-1004-induced relaxation, thereby suggesting that this compound does not act through these membrane receptor associated mechanisms. HA-1004 shifted the dose-response curve for CaCl2 to the right in a competitive manner in depolarized rabbit renal arterial strips. This compound also relaxed the A-23187 and phenylephrine-induced contractions elicited in Ca++-free solution. These findings suggest that HA-1004 exerts its action at the intracellular or submembranal level. This vasodilator has little effect on actomyosin adenosine triphosphatase and Ca++-calmodulin-dependent myosin light chain kinase. Studies using its derivatives with various lengths of alkyl chain (C0-C6) indicated that the potencies of these compounds, as vasorelaxants, correlated well with their potential to inhibit cyclic nucleotide-dependent protein kinase. HA-1004 should be a useful tool for investigating in smooth muscle, regulatory mechanism(s) by second messengers, cyclic AMP and cyclic GMP.

Adenosine Triphosphatases↗
PubMed1985

Macromolecular permeability of the tight junction of the human nasal mucosa.

Using HRP as a cytochemical tracer, we investigated the tight junctional permeability of the human nasal mucosa in the early stage of its transportation. We found that the tight junction becomes "leaky" in the inflammatory and in the allergic conditions. Connection of goblet-goblet and goblet-ciliated cells were weaker than that of ciliated-ciliated cells. All epithelial tight junctions seemed to be loose in cases of allergic rhinitis.

Biological Transport↗
PubMed1984

Serotonin secretion from human platelets may be modified by Ca2+-activated, phospholipid-dependent myosin phosphorylation.

1-(5-Isoquinolinesulfonyl)-2-methylpiperazine (H-7), which has been identified as a potent inhibitor of protein kinase C in vitro (Hidaka, H., Inagaki, M., Kawamoto, S., and Sasaki, Y. (1984) Biochemistry, in press), enhanced serotonin release from human platelets that was induced by the 12-O-tetradecanoyl phorbol 13-acetate and correspondingly decreased incorporation of radioactive phosphate into a 20,000-dalton protein. H-7 did not affect the protein phosphorylation or the serotonin secretion in unstimulated platelets. A phosphopeptide with a molecular weight of 20,000 has previously been identified as a light chain (LC20) of platelet myosin and both protein kinase C and Ca2+-calmodulin-dependent myosin light-chain kinase have been shown to be involved in its phosphorylation. Two-dimensional peptide mapping following tryptic hydrolysis revealed that H-7 selectively inhibited the protein kinase C-catalyzed phosphorylation of myosin light chain. This pharmacological evidence suggests that Ca2+-activated, phospholipid-dependent myosin light-chain phosphorylation may play an inhibitory role in the release reaction.

1-(5-Isoquinolinesulfonyl)-2-Methylpiperazine↗
PubMed1984

The role of serotonin in mucociliary transport system in the ciliated epithelium of frog palatine mucosa.

The effects of serotonin (5-hydroxytryptamine, 5-HT) on mucociliary transport and mucus secretion were investigated pharmacologically. The presence of 5-HT in the ciliated epithelium of frog palatine mucosa was examined chromatographically. Mucociliary transport was accelerated by the application of 10(-6) M 5-HT. Mucus secretion was also stimulated significantly by 5-HT (30 mg/kg). 5-HT in the mucosa was detected by a chromatographic technique when a large amount of 5-HT precursor, 5-hydroxytryptophan (5-HTP), was given previously. Phenylhydrazine was used as MAO inhibitor. When phenylhydrazine (20 mg/kg) was given before 5-HTP, 5-HT was markedly concentrated in the mucosa. Radioactive 5-HT was also detected in the mucosa after incubation with [14C]5-HTP. One hour after systemic administration of [3H]5-HTP, a large number of silver grains appeared in the autoradiograms of some epithelial cells. These results suggest the possibility that epithelial cells with the ability to synthesize 5-HT from 5-HTP exist in ciliated epithelium. A possible functional relationship is proposed between the regulation of mucociliary transport with mucus secretion and 5-HT-containing cells.

5-Hydroxytryptophan↗
PubMed1984

Isoquinolinesulfonamides, novel and potent inhibitors of cyclic nucleotide dependent protein kinase and protein kinase C.

Naphthalenesulfonamides such as N-(6-amino-hexyl)-5-chloro-1-naphthalenesulfonamide (W-7) are potent calmodulin (CaM) antagonists and act upon several protein kinases at higher concentration. When the naphthalene ring was replaced by isoquinoline, the derivatives were no longer CaM antagonists but retained the ability to inhibit protein kinases, and some of the derivatives exhibited selective inhibition toward a certain protein kinase. cAMP-dependent, cGMP-dependent, and Ca2+-phospholipid-dependent (protein kinase C) protein kinases were inhibited significantly by addition of 10(-6) M N-[2-(methylamino)ethyl]-5-isoquinoline-sulfonamide (H-8) and 1-(5-isoquinolinylsulfonyl)-2-methylpiperazine (H-7). H-8 was the most active of the inhibitors in this series and inhibited more markedly cyclic nucleotide dependent protein kinases, than other kinases, while the derivative with the sulfonylpiperazine residue (H-7) was the most potent in inhibiting protein kinase C. Apparent Ki values of H-8 were 0.48 and 1.2 microM for cGMP-dependent and cAMP-dependent protein kinases, respectively, and the Ki value of H-7 for protein kinase C was 6 microM. Both the holoenzyme and the catalytic subunit (or fragment), which is active without an enzyme activator, are susceptible to these compounds with a similar concentration dependency, thereby indicating that the inhibitory effect is attributed to the direct interaction of the compound with the active center of the enzyme but not with the enzyme activator. The inhibitions were freely reversible and of the competitive type with respect to ATP and of the noncompetitive type with respect to the phosphate acceptor.(ABSTRACT TRUNCATED AT 250 WORDS)

Actomyosin↗
PubMed1984

Two types of calmodulin antagonists: a structurally related interaction.

The ability of several calmodulin (CaM) antagonists, such as N-(6-aminohexyl)-5-chloro-1-naphthalene sulfonamide (W-7) and trifluoperazine, to displace [3H]-W-7 from CaM correlated with the inhibition of Ca2+-CaM-dependent phosphodiesterase (PDE) by these agents. These antagonists also suppressed the increase in fluorescence of n-phenyl-1-naphthylamine (NPN) by complex formation with CaM in the presence of Ca2+. However, the ability of some CaM antagonists, such as prenylamine and butaclamol, to displace [3H]-W-7 from CaM did not correlate with the inhibition of Ca2+-PDE. These antagonists enhanced the increase in fluorescence of NPN by complex formation with CaM in the presence of Ca2+. In a study employing 1H-nuclear magnetic resonance, the spectrum changes of the aromatic region of CaM induced by prenylamine were significantly more marked than the changes induced by W-7. These findings suggest two types of CaM antagonists. The compounds in each of the groups appear to have common molecular structures.

Animals↗
PubMed1984

[Immunohistochemical demonstration of carcinoembryonic antigen and ultrastructural features of endometrial adenocarcinoma].

Determination of carcinoembryonic antigen levels in plasma (45 cases) and the immunohistochemical demonstration of tumor CEA (37 cases) were carried out in patients with endometrial adenocarcinoma. Twenty four out of 37 were also studied with the electron microscope. The plasma CEA level prior to therapy was significantly elevated (greater than 5.0ng/ml) in only one case (1/45:2.2%) of endometrial adenocarcinoma. CEA levels were more consistently elevated (4/17:23.5%) in patients with cervical adenocarcinoma. Immunoperoxidase staining of CEA (PAP method) was carried out using formalin-fixed paraffin embedded sections of 37 tumors. Tissue CEA activities were found in 9 out of 37 endometrial adenocarcinomas (24.3%) and 19 of 23 cervical adenocarcinomas (82.6%). Immunoreactive CEA was present in a high concentration on the cell surface of endometrial glands and less dense in their cytoplasm. In 9 of CEA positive endometrial carcinoma tissues, squamous metaplastic lesions were found in 4 cases and mucinous metaplasia in one case which were all CEA positive. With regard to the histopathological grade, CEA positive specimens were categorized G1 (4) and G2 (5) and all of the G3 were CEA negative. Seven of 9 cases of CEA positive specimens were examined under the electron microscope. There was no definite tendency in their ultrastructural characteristics, but all of the specimens examined revealed abundant cytoplasmic organelles suggestive of intracytoplasmic differentiation analogous to those of endometrial cells in proliferative phase. Moreover, fine structures of squamous and mucinous metaplastic cells were also described in detail.

Adenocarcinoma↗
PubMed1983

Hydrophobic properties of Tetrahymena calmodulin related to the phosphodiesterase activity.

We have examined hydrophobic properties of Tetrahymena CaM using the uncharged probe, n-phenyl-1-naphthylamine (NPN) fluorescence. The maximal fluorescence intensity of Tetrahymena calmodulin (CaM) is less than 1/12 of that of the bovine brain CaM. In the phosphodiesterase activation, the potency of Tetrahymena CaM, which was represented by reciprocals of the quantity of CaM required for half-maximal activation of enzyme was 22.7% respectively, of that of the bovine brain CaM. Here, Tetrahymena CaM had less hydrophobic groups exposed in the presence of Ca2+. Then Ca2+-CaM dependent enzymes require much amount of Tetrahymena CaM, comparing with the bovine brain CaM.

1-Naphthylamine↗
PubMed1983

Absorption of various drugs through the rabbit's respiratory mucosa in vitro.

The absorption of doxycycline (DOTC), bekanamycin (AKM), cefazolin (CEZ), penicillin G (PC-G), prednisolone, and human IgG through the rabbit's tracheal mucosa was examined using the double-chamber method. The results indicate that the tracheal mucosa can absorb both small molecules and macromolecules. Passing through the intercellular space, DOTC, a small molecule, was absorbed through the tracheal epithelium by diffusion. Human IgG, a macromolecule, was absorbed by the mechanism of an energy-consuming transport process. This study of the absorption of drugs through the respiratory mucosa could open up new areas in the utilization of intrarespiratory administration of drugs and lead to a better understanding of the mechanisms involved in respiratory allergies.

Absorption↗
PubMed1983

Calmodulin antagonists enhance calcium binding to calmodulin.

The effects of calmodulin (CaM) antagonists, N-(6-aminohexyl)(-5-chloro-1-naphthalenesulfonamide (W-7) and its derivatives or trifluoperazine (TFP) on the Ca2+ binding to CaM were investigated. In the presence of these CaM antagonists, the extent of the Ca2+ binding to CaM increased. Stoichiometrical Examination showed that these CaM antagonists dose-dependently increased the sensitivity of all four Ca2+ binding sites on CaM. An analysis of CaM by UV spectroscopy revealed that the conformation of the Ca2+ CaM complex in the presence and absence of these CaM antagonists differed. Therefore, binding of this CaM antagonist to CaM increase the binding of Ca2+ to this protein.

Animals↗