Control of the phasic and tonic contractions of guinea pig stomach by a ryanodine-sensitive Ca2+ store
| Autor: | Kiril K. Boev, Georgi V. Petkov |
|---|---|
| Rok vydání: | 1999 |
| Předmět: |
Male
Ruthenium red medicine.medical_specialty Indoles Guinea Pigs Calcium-Transporting ATPases In Vitro Techniques Biology Thromboplastin Tonic (physiology) chemistry.chemical_compound Isometric Contraction Internal medicine Pyloric Antrum medicine Animals Drug Interactions Gastric Fundus Enzyme Inhibitors Antrum Pharmacology Dose-Response Relationship Drug Voltage-dependent calcium channel Ryanodine Ryanodine receptor Stomach Muscle Smooth Ruthenium Red Acetylcholine Sarcoplasmic Reticulum Endocrinology chemistry Gastric Mucosa Calcium Calcium Channels medicine.symptom Cyclopiazonic acid Muscle Contraction Muscle contraction medicine.drug |
| Zdroj: | European Journal of Pharmacology. 367:335-341 |
| ISSN: | 0014-2999 |
| DOI: | 10.1016/s0014-2999(98)00875-9 |
| Popis: | In some smooth muscle cells, the rise in intracellular Ca 2+ as a result of a Ca 2+ influx via plasma membrane Ca 2+ channels can activate a further increase in intracellular Ca 2+ as a result of Ca 2+ release from intracellular stores. This study examined the role of the Ca 2+ -induced Ca 2+ release from the ryanodine-sensitive intracellular Ca 2+ stores in shaping the smooth muscle contractions of guinea pig stomach. The contractile activity of isolated muscle strips of the fundus, corpus and antrum region of the stomach was recorded under isometric conditions. Ryanodine, an activator of Ca 2+ -induced Ca 2+ release, concentration dependently (10 −7 –3.10 −5 M) increased the tone of fundus and corpus strips. Ryanodine had a dual action on the phasic contractions of the antrum and corpus: increase by the low concentrations (up to 10 −6 M) and inhibition by the high concentrations (10 −6 –3.10 −5 M). Nifedipine (10 −5 M) completely inhibited the ryanodine (10 −6 M)-induced phasic contractions and only partly the ryanodine (3.10 −5 M)-induced tonic contractions. In the presence of 10 −5 M cyclopiazonic acid, a specific inhibitor of sarcoplasmic reticulum Ca 2+ -ATPase, ryanodine (3.10 −5 M) further increased the tone of the corpus and fundus strips. Ryanodine (3.10 −5 M) induced tonic contractions in the fundus and corpus precontracted by acetylcholine (10 −5 M), and inhibited the acetylcholine (10 −6 M)-induced phasic contractions in the antrum and corpus. Ruthenium red, an inhibitor of Ca 2+ -induced Ca 2+ release, concentration dependently (10 −6 –10 −4 M) decreased the tone and amplitude of the phasic contractions. The data obtained provide evidence for the participation of a sarcoplasmic reticulum Ca 2+ -induced Ca 2+ release mechanism in shaping the tonic and phasic contractions of guinea pig stomach, and highlight important tissue differences. |
| Databáze: | OpenAIRE |
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