Regulation of Ca2+sensitization by PKC and rho proteins in ovine cerebral arteries: effects of artery size and age
| Autor: | Lubo Zhang, William J. Pearce, Sergey E. Akopov |
|---|---|
| Rok vydání: | 1998 |
| Předmět: |
Aging
Serotonin medicine.medical_specialty Physiology G protein Cerebral arteries Exotoxins Biology chemistry.chemical_compound GTP-Binding Proteins Pregnancy 1-(5-Isoquinolinesulfonyl)-2-Methylpiperazine Physiology (medical) Internal medicine medicine Animals Enzyme Inhibitors Neurotransmitter Protein Kinase C Protein kinase C Escin Sheep Cerebral Arteries Enzyme Activation medicine.anatomical_structure Endocrinology chemistry Guanosine 5'-O-(3-Thiotriphosphate) Circulatory system Calcium Female rhoA GTP-Binding Protein Cardiology and Cardiovascular Medicine Intracellular Blood vessel Artery |
| Zdroj: | American Journal of Physiology-Heart and Circulatory Physiology. 275:H930-H939 |
| ISSN: | 1522-1539 0363-6135 |
| DOI: | 10.1152/ajpheart.1998.275.3.h930 |
| Popis: | G protein-regulated Ca2+sensitivity of vascular contractile proteins plays an important role in cerebrovascular reactivity. The present study examines the intracellular mechanisms that govern G protein-regulated Ca2+sensitivity in cerebral arteries of different size and age. We studied β-escin-permeabilized segments of common carotid, basilar, and middle cerebral arteries from nonpregnant adult and near-term fetal sheep. Activation of protein kinase C (PKC) by (−)-indolactam V or a phorbol ester produced receptor-independent increases in Ca2+sensitivity. Such increases were more marked in immature arteries and were inversely correlated with artery size in both mature and immature arteries. However, inhibitors of PKC did not significantly affect increases in Ca2+sensitivity in responses to either serotonin (5-hydroxytryptamine, 5-HT) or guanosine 5′- O-(3-thiotriphosphate) (GTPγS). Alternatively, deactivation of rho p21, a small G protein associated with Rho kinase, by exotoxin C3 fully prevented increases in Ca2+sensitivity in responses to 5-HT or GTPγS in both adult and fetal arteries of all types. Neither inhibitors of PKC nor exotoxin C3 altered baseline Ca2+sensitivity. We conclude that patterns of receptor- and/or G protein-mediated modulation of Ca2+sensitivity are dependent on an intracellular pathway that involves activation of small G proteins and Rho kinase. In contrast, PKC has little, if any, role in agonist-induced Ca2+sensitization under the present experimental conditions. |
| Databáze: | OpenAIRE |
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