GABAB receptor-mediated mechanisms in the RVLM studied by microinjections of two GABAB receptor antagonists
| Autor: | C.E. Cogo, R. Ermirio, D. Blanchi, L. C. Weaver, G. L. Avanzino, Piero Ruggeri |
|---|---|
| Rok vydání: | 1994 |
| Předmět: |
Male
medicine.medical_specialty Mean arterial pressure Baclofen Microinjections Physiology Blood Pressure GABAB receptor Inhibitory postsynaptic potential Functional Laterality chemistry.chemical_compound Electrocardiography Organophosphorus Compounds Heart Rate Physiology (medical) Internal medicine medicine Animals Homeostasis Rats Wistar Microinjection Medulla Oblongata Chemistry Muscimol Rostral ventrolateral medulla Rats Endocrinology Receptors GABA-B Cardiology and Cardiovascular Medicine GABA-B Receptor Antagonists |
| Zdroj: | The American journal of physiology. 266(5 Pt 2) |
| ISSN: | 0002-9513 |
| Popis: | The cardiovascular effects of microinjections of two gamma-aminobutyric acid (GABA) antagonists specifically acting on GABAB receptors, 2-hydroxy-saclofen (2-OH-S) and CGP-35348, into vasopressor sites of rostral ventrolateral medulla (RVLM) were studied in rats anesthetized with urethan. Bilateral microinjection of 2-OH-S induced significant increases in mean arterial pressure (MAP) and heart rate (HR) in 21 of 26 RVLM vasopressor sites (81%); average increases obtained in the 26 sites studied were +25.2 +/- 3.0 mmHg and +12.7 +/- 2.1 beats/min. Bilateral microinjection of CGP-35348 induced significant increases in MAP and HR in 10 of 12 RVLM sites (83%). Average increases in the 12 sites studied were +27.6 +/- 3.9 mmHg and +14.6 +/- 2.5 beats/min. Sixteen rats received unilateral electrolytic lesions of one RVLM. Microinjections of either 2-OH-S or CGP-35348 into vasopressor sites within the intact RVLM significantly antagonized the depressor responses observed after injections of baclofen (20 pmol) into the same sites, whereas both GABAB antagonists did not affect the depressor response induced by microinjection of muscimol (5 pmol). These results suggest a tonic inhibitory mechanism within the RVLM mediated by GABAB receptors involved in central cardiovascular regulation. |
| Databáze: | OpenAIRE |
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