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Biomedical subjects

J Minamikawa

Publications and source records attributed to J Minamikawa.

45 records · Page 3Linked to original sources
PubMed1978

Studies in the (+)-morphinan series. 5. Synthesis and biological properties of (+)-naloxone.

(+)-Naloxone was prepared in 26% overall yield in eight steps from (+)-7-bromodihydrocodeinone dimethyl ketal by a synthesis which excluded enantiomeric contamination. (+)-Naloxone was examined in three assay systems and found to have no more than 1/1000(-1)/10 000th the activity of (-)-naloxone; it can, thus, serve to test the stereospecificity of the biochemical and pharmacological actions of (-)-naloxone.

Adenylyl Cyclases↗
PubMed1978

Synthesis and antinociceptive activity of 7-methoxycodeine.

(-)-7-Methoxycodeine was synthesized from (-)-1-bromosinomeninone in three steps with an overall yield of 29%. The introduction of the 7-methoxy group into the C ring of codeine did not decrease its oral activity. 7-Methoxycodeine was unstable in acidic media. Its oral activity was however, not likely to be due to conversion to the acid-stable (-)-sinomeninone, since the latter was orally inactive.

Administration, Oral↗
PubMed1977

Stereospecific and nonstereospecific effects of (+)- and (-)-morphine: evidence for a new class of receptors?

The unnatural (+) enantiomer of morphine had minimal activity in three opiate assays in vitro: the rat brain homogenate binding assay, the electrically stimulated guinea pig ileum assay, and the inhibition of adenylate cyclase in neuroblastoma X glioma hybrid cell homogenates. When (+)-morphine was microinfected into the periaqueductal gray (a site known to mediate morphine analgesia) of drug-naive rats, there was only minimal analgesia, but the hyperresponsivity usually observed after microinfection of (-)-morphine occurred. Also, when (+)-morphine was microinfected into the midbrain reticular formation of drug-naive rats, rotation similar to that following microinjection of (-)-morphine occurred. These behaviors were not blocked by naloxone. Significantly, they typically occur in precipitated abstinence in morphine-dependent rats. These observations suggest that there are at least two classes of receptors, one stereospecific and blocked by naloxone and the other only weakly stereospecific and not blocked by naloxone, and that precipitated abstinence may be due, in part, to a selective blockade of receptors of the former class but not of the latter.

Adenylyl Cyclase Inhibitors↗