Differential tachykinin receptor subtype activation in capsaicin and KCl contractions of guinea pig trachealis
| Autor: | I. M. Ndukwu, K. Uzendoski, Alan R. Leff, A. Herrnreiter, Julian Solway, Richard W. Mitchell, B. Gitter |
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| Rok vydání: | 1995 |
| Předmět: |
Male
Pulmonary and Respiratory Medicine medicine.medical_specialty Contraction (grammar) Physiology medicine.drug_class Guinea Pigs Stimulation In Vitro Techniques Potassium Chloride Guinea pig chemistry.chemical_compound Isometric Contraction Physiology (medical) Internal medicine Muscarinic acetylcholine receptor medicine Animals Tromethamine Receptors Tachykinin Dose-Response Relationship Drug Osmolar Concentration Muscle Smooth Cell Biology Receptor antagonist Electric Stimulation Trachea Glucose Endocrinology chemistry Capsaicin Trachealis muscle Tachykinin receptor |
| Zdroj: | American Journal of Physiology-Lung Cellular and Molecular Physiology. 269:L837-L842 |
| ISSN: | 1522-1504 1040-0605 |
| DOI: | 10.1152/ajplung.1995.269.6.l837 |
| Popis: | We assessed the role of endogenously secreted tachykinins in mediating contraction caused by potassium chloride (KCl) in guinea pig tracheal smooth muscle (TSM) strips in vitro. Maximal isometric contraction was elicited with approximately 45 mM KCl and was 196 +/- 8% of the response to electrical field stimulation (% EFS) in the same tissues. Muscarinic receptor blockade with atropine modestly attenuated this contraction caused by KCl to 175 +/- 9 %EFS (P < 0.05), and treatment with a selective neurokinin subtype 1 (NK1) receptor antagonist, LY-297911, caused even greater inhibition of KCl-elicited contraction to 124 +/- 8 %EFS (P < 0.001). By contrast, SR-48968, a selective NK2 antagonist, had no effect on contraction caused by KCl (183 +/- 9 %EFS; P = NS vs. KCl alone). However, given together at the same concentration, SR-48968 augmented the inhibition of contraction caused by LY-297911 to 93 +/- 15 %EFS (P < 0.05 vs. LY-297911 alone). In contrast to the effect on KCl-induced contraction, LY-297911 caused only moderate inhibition of the contraction caused by capsaicin to 81 +/- 13 %EFS (P < 0.05 vs. control, 114 +/- 15 %EFS), whereas SR-48968 caused substantial attenuation of contraction caused by capsaicin to 23 +/- 5 %EFS (P < 0.005 vs. LY-297911). We demonstrate that a significant portion of the contraction caused by KCl, in addition to capsaicin, is elicited in guinea pig TSM through neurokinin secretion. However, NK1 receptors predominantly mediate contraction caused by KCl, and NK2 receptors predominantly mediate contraction elicited by capsaicin in guinea pig airway smooth muscle. |
| Databáze: | OpenAIRE |
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