6533b86dfe1ef96bd12ca0fe
RESEARCH PRODUCT
The effects of racemic bethanechol and its (R)- and (S)-enantiomers on pre- and postjunctional muscarine receptors in the guinea-pig ileum
Günter LambrechtErnst MutschlerH. SchwörerHeinz Kilbingersubject
MaleStereochemistryGuinea PigsMyenteric PlexusBethanecholchemistry.chemical_compoundBethanechol CompoundsIleumMuscarinic acetylcholine receptormedicineAnimalsPharmacologyMuscarineChemistryMuscle SmoothStereoisomerismGeneral MedicineSmooth muscle contractionBethanecholReceptors MuscarinicRacemic mixtureFemaleCholinesterase InhibitorsEnantiomermedicine.symptomAcetylcholineMuscle Contractionmedicine.drugMuscle contractiondescription
The effect of racemic bethanechol and its (R)- and (S)-enantiomers on smooth muscle contraction and outflow of [3H]-acetylcholine were studied in the guinea-pig myenteric plexus-longitudinal muscle preparation that had been preincubated with [3H]-choline. (S)-, racemic, and (R)-bethanechol caused concentration-dependent contractions of the longitudinal muscle. The potency ratio of the strong isomer (S) to the weak one (R) was 915. Racemic and (S)-bethanechol concentration-dependently inhibited the evoked outflow of [3H]-acetylcholine. Racemic bethanechol was more potent than (S)-bethanechol. (R)-bethanechol up to a concentration of 1 mM did no affect the evoked outflow of [3H]-acetylcholine. (S)-bethanechol was a substrate, and (R)-bethanechol a weak inhibitor of the tissue cholinesterases. The weak cholinesterase-inhibiting action of the (R)-enantiomer probably reinforces the prejunctional effects of the (S)-enantiomer in the racemic mixture.
| year | journal | country | edition | language |
|---|---|---|---|---|
| 1985-12-01 | Naunyn-Schmiedeberg's Archives of Pharmacology |