Calcium-induced vasocontractions after alpha-2 adrenergic receptor activation in the dog saphenous vein: comparison to calcium-induced contractions after potassium-depolarization
| Autor: | J. F. DeBernardis, R. B. Warner, J. Y. Lee, M. E. Brune |
|---|---|
| Rok vydání: | 1990 |
| Předmět: |
Male
medicine.medical_specialty Phenoxybenzamine Rauwolscine chemistry.chemical_element Calcium In Vitro Techniques Muscle Smooth Vascular chemistry.chemical_compound Norepinephrine Dogs Nifedipine Internal medicine medicine Animals Saphenous Vein Adrenergic alpha-Antagonists Pharmacology Voltage-dependent calcium channel Chemistry Calcium channel Receptors Adrenergic alpha Calcium Channel Blockers Endocrinology Neuromuscular Depolarizing Agents Potassium Verapamil Female Calcium Channels medicine.symptom medicine.drug Muscle contraction Muscle Contraction |
| Zdroj: | General pharmacology. 21(5) |
| ISSN: | 0306-3623 |
| Popis: | 1. Calcium mediated contractile effects were evoked in phenoxybenzamine (10(-7) M)-pretreated dog saphenous vein (DSV) rings under the continuing presence of norepinephrine (3 x 10(-5) M), a condition that selectively activates alpha 2 (alpha 2)-adrenergic receptors. 2. Calcium-induced contractions in this model were dose-dependently inhibited by the alpha 2 antagonists rauwolscine and SKF-86466, while the calcium channel blockers nifedipine and verapamil produced only small non-dose related inhibitions. The receptor antagonists sulpiride, buspirone, pyrilamine and atropine showed no inhibitory effect. 3. In contrast, rauwolscine and SKF-86466 produced no inhibition of the calcium-evoked contractions in potassium-depolarized DSV rings, in which nifedipine and verapamil exhibited potent calcium antagonist activity. 4. These data provide evidence to support the presence of alpha 2 related receptor-operated calcium channels in vascular smooth muscle, which are pharmacologically distinguishable from potential-dependent calcium channels. |
| Databáze: | OpenAIRE |
| Externí odkaz: |
|