title: Influence of tacrine on dopamine-induced reactions of the gastric smooth muscle of rats.
abstract: The clinical usage of the cholinesterase inhibitor tacrine for treatment of Alzheimer's disease is accompanied by adverse effects on the gastrointestinal tract. These adverse effects are a result of the direct action of tacrine on the intestinal smooth muscles or of the modulation of certain neurotransmitters regulating gastrointestinal functions. Dopamine is a neurotransmitter that modulates gastrointestinal motility. This study was designed to examine in vitro the effects of tacrine on dopamine-induced changes in spontaneous activity of smooth muscle preparations from rat's gastric corpus. The mechanical activity was isometrically registered. Tacrine 1.10(-7)-1.10(-5) mol/l caused smooth muscle contraction, which was blocked by atropine 1.10(-6) mol/l. Tacrine 1.10(-4) mol/l provoked a relaxation resistant to atropine. Dopamine and D(2)-receptor antagonists haloperidol and R121 had no effect on tacrine-induced relaxation. Dopamine-induced contraction was concentration-dependent. It was blocked by D(2)-receptor antagonists haloperidol and R121 and by tacrine 1.10(-4) mol/l. In the presence of tacrine 1.10(-7)-10(-5) mol/l or atropine the dopamine-induced contraction was significant. The data obtained suggested that tacrine 1.10(-4) mol/l inhibited the dopamine effects on gastric corpus smooth muscles. The effect was probably not dependent on its anticholinesterase activity or not realized through direct influence on D(2)-dopamine receptors.
authors.affiliation: Department of Physics and Biophysics, Sofia, Bulgaria. dgetova@hotmail.com
authors.forename: V
authors.initials: V
authors.lastname: Turijski
authors.forename: A
authors.initials: A
authors.lastname: Krustev
authors.forename: D
authors.initials: D
authors.lastname: Getova-Spassova
authors.forename: V
authors.initials: V
authors.lastname: Spassov
mesh_terms: D000818:Animals; D001285:Atropine / Q000494:pharmacology; D004298:Dopamine / Q000494:pharmacology*; D065127:Dopamine D2 Receptor Antagonists; D004305:Dose-Response Relationship, Drug; D004359:Drug Therapy, Combination; D006220:Haloperidol / Q000494:pharmacology; D008297:Male; D009119:Muscle Contraction / Q000187:drug effects / Q000502:physiology; D009126:Muscle Relaxation / Q000187:drug effects / Q000502:physiology; D009130:Muscle, Smooth / Q000187:drug effects* / Q000502:physiology; D020891:Raclopride / Q000494:pharmacology; D051381:Rats; D017208:Rats, Wistar; D011950:Receptors, Cholinergic / Q000187:drug effects; D017448:Receptors, Dopamine D2 / Q000187:drug effects; D013270:Stomach / Q000166:cytology / Q000187:drug effects*; D013619:Tacrine / Q000037:antagonists & inhibitors / Q000494:pharmacology*; D013997:Time Factors
chemical_list: D065127:Dopamine D2 Receptor Antagonists; D011950:Receptors, Cholinergic; D017448:Receptors, Dopamine D2; D020891:Raclopride; D013619:Tacrine; D001285:Atropine; D006220:Haloperidol; D004298:Dopamine