Postjunctional effect of pinacidil on contractility of isolated bovine trachealis
| Autor: | K Rehder, Vito Brusasco, Emanuele Crimi, D Rocchi, M Lazzarotti, Pingfang Song |
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| Rok vydání: | 1996 |
| Předmět: |
Pulmonary and Respiratory Medicine
Potassium Channels Muscle Relaxation Pharmacology Guanidines Neuromuscular junction Contractility chemistry.chemical_compound Glyburide medicine Animals Dose-Response Relationship Drug business.industry Pinacidil Cell Membrane Muscle Smooth Stereoisomerism musculoskeletal system Potassium channel Acetylcholine Electric Stimulation Receptors Neurotransmitter Trachea medicine.anatomical_structure Muscle relaxation chemistry Anesthesia cardiovascular system Trachealis muscle Cattle medicine.symptom business medicine.drug Muscle contraction Histamine Muscle Contraction |
| Zdroj: | The European respiratory journal. 9(10) |
| ISSN: | 0903-1936 |
| Popis: | Potassium channel openers hyperpolarize the smooth muscle cell membrane and relax airway smooth muscle. In this study, pre- and postjunctional effects of pinacidil ((+/-) N-cyano-N'-(4-pyridil)-N"-(1,2,2-trimethylpropyl)-guanidine monohydrated), an adenosine triphosphate (ATP)-sensitive K(+)-channel opener, were determined in isolated bovine trachealis. The effects of pinacidil on the frequency-response to electrical field stimulation (EFS), 0.1-32 Hz, and on the concentration response to acetylcholine (ACh), 10(9)-10(-4) M, were compared in muscle strips from six animals. In addition, the effect of pinacidil on the inhibitory nonadrenergic noncholinergic (iNANC) system was evaluated in histamine-contracted muscle strips from another eight animals. Pinacidil (10(-6) or 10(-5) M) shifted both the EFS frequency-response and the ACh concentration-response curves significantly (p < 0.01) to the right. Glibenclamide (10(-7)-10(-5) M) antagonized these responses in a concentration-dependent manner. The inhibitory effects of pinacidil on contractions of the same magnitude induced by EFS or exogenous ACh were not significantly different (p = 0.11), suggesting that pinacidil had only a postjunctional effect. Pinacidil had no effect on iNANC-mediated muscle relaxation. We conclude that pinacidil attenuates the contraction of isolated bovine tracheal smooth muscle by postjunctional mechanisms. |
| Databáze: | OpenAIRE |
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