G-proteins in alpha 1-adrenoceptor mediated prostatic smooth muscle contraction
| Autor: | P. Drescher, R. E. Eckert, Paul O. Madsen |
|---|---|
| Rok vydání: | 1994 |
| Předmět: |
Male
medicine.medical_specialty Contraction (grammar) Nifedipine G protein Urology Prostatic Hyperplasia Biology Pertussis toxin Contractility Phenylephrine GTP-Binding Proteins Internal medicine medicine Prazosin Humans Virulence Factors Bordetella Adrenergic alpha-Antagonists Prostate Muscle Smooth Smooth muscle contraction Receptors Adrenergic alpha Endocrinology Pertussis Toxin Potassium medicine.drug Muscle Contraction Signal Transduction |
| Zdroj: | Urological research. 22(3) |
| ISSN: | 0300-5623 |
| Popis: | The role of signal transducing guanine-nucleotide binding proteins (G-proteins) in alpha 1-receptor mediated smooth muscle contractions was investigated in human hyperplastic prostatic tissue. The selective alpha 1-receptor agonist phenylephrine (PE) evoked dose dependent contractions antagonized by the alpha 1-receptor blockers prazosin (EC50 10 nM) and YM617 (EC50 3 nM). Application of nifedipine (1-10,000 nM), a blocker of voltage-dependent L-type Ca(2+)-channels (VDCC), inhibited the PE evoked contraction up to 65.4%. Pretreating the tissue strips with pertussis toxin (PTX, exotoxin from Bordetella pertussis; 5-25 micrograms/ml), inactivating a subpopulation of G-proteins, inhibited the PE induced contractions up to 73.9%. PTX pretreatment had no effect on contractions elicited by 125 mM K+. Application of nifedipine to PTX pretreated tissue led to an additional inhibition of 13.7%. Our findings demonstrate the involvement of PTX-sensitive G-proteins in the signal transduction pathway of alpha 1-receptor induced contractions of prostatic smooth muscle. The remaining contractility of PTX pretreated tissue suggests additional participation of PTX insensitive mechanisms in alpha 1-receptor mediated prostatic smooth muscle contractions. |
| Databáze: | OpenAIRE |
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