Cyclopiazonic acid-induced changes in contractile activity of smooth muscle strips isolated from cat and guinea-pig stomach
| Autor: | Kiril K. Boev, Georgi V. Petkov |
|---|---|
| Rok vydání: | 1996 |
| Předmět: |
Nitroprusside
medicine.medical_specialty Indoles Time Factors Vasodilator Agents Guinea Pigs Calcium-Transporting ATPases In Vitro Techniques Biology Nitroarginine Tonic (physiology) chemistry.chemical_compound Internal medicine medicine Animals Antrum Pharmacology Stomach Muscle Smooth Acetylcholine Endocrinology chemistry Molsidomine Cats Tetrodotoxin Calcium Sodium nitroprusside Nitric Oxide Synthase medicine.symptom Cyclopiazonic acid Muscle Contraction medicine.drug Muscle contraction |
| Zdroj: | European Journal of Pharmacology. 318:109-115 |
| ISSN: | 0014-2999 |
| DOI: | 10.1016/s0014-2999(96)00764-9 |
| Popis: | The effects of cyclopiazonic acid (CPA), a specific inhibitor of sarcoplasmic reticulum Ca(2+)-ATPase, on contractile activity of circular smooth muscle strips isolated from the antrum, corpus and fundus regions of the cat and guinea-pig stomach were studied. Contractile activity was recorded under isometric conditions, in organ baths. CPA, concentration dependently (3 x 10(-7)-3 x 10(-5) M) increased the tone of the cat and guinea-pig gastric fundus and corpus as well as the amplitude of the phasic contractions of the cat corpus and antrum, affecting their frequency. CPA had a dual action on the phasic contractions of the guinea-pig antrum: an increase at low concentrations (up to 10(-6) M) and inhibition at high concentrations (10(-6)-3 x 10(-5) M). Tetrodotoxin (10(-6) M), atropine (10(-6) M) and N omega-nitro-L-arginine (10(-4) M) did not change significantly the effects of CPA. Nifedipine completely inhibited the CPA-induced phasic contractions and partly inhibited the CPA-induced tonic contractions. The nitric oxide-releasing agents, sodium nitroprusside (10(-3) M) and 3-morpholino-sydnonimine (10(-3) M), completely inhibited the CPA-induced tonic and phasic contractions. CPA induced tonic contractions in the cat and guinea-pig gastric fundus precontracted by acetylcholine (10(-5) M) and inhibited the acetylcholine (10(-6) M)-induced phasic contractions in the guinea-pig gastric antrum and corpus. The results suggest multiple roles for sarcoplasmic reticulum Ca2+ stores and sarcoplasmic reticulum Ca(2+)-ATPase in the shaping of spontaneous and evoked tonic and phasic contractions of the stomach, and highlight important species and tissue differences. |
| Databáze: | OpenAIRE |
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