Which of the following sympathetic receptors acts as vasoconstriction and vasodilatation:: (A) Alpha 1 and Alpha 2, (B) Alpha 1 and Beta 1, (C) Alpha 1 and Beta 2, (D) Beta 1 and Beta 2
Answer is C. (Ref: Katzung 14th ed. pg. 145-47)Alpha 1 and Beta 2 receptors present at blood vessels causing vasoconstriction and vasodilatation respectively.Sympathetic receptors, their location, function and G protein.ReceptorLocationFunctionG-Proteina1BV, smooth muscle, Salivary glandsVasoconstriction Increase secretionGqa2Presynapse Beta pancreatic cellBrake/Inhibit NA releaseDecrease insulin releaseGib1Heart JG cellInc Heart rate Renin releaseGsb2LungsSmooth muscle LiverBronchodilatation Relaxation of smooth muscles GlycogenolysisGsb3Adipocyte Detrusor muscleLipolysis, thermogenesis Bladder relaxGs