Question

1. Mr. L. works at a pharmaceutical company and is accidentally exposed to an adrenergic antagonist. (23 points total)

1. What specific receptors would an adrenergic antagonist affect? (1)

2. What neurotransmitter(s) usually binds to these receptors? (1)

3. What coupling mechanism is associated with the binding of neurotransmitter to these receptors and how would this change membrane potential on the target cells? (2)

4. Name a degrading enzyme that inactivates this neurotransmitter and indicate where it is found (2)

5. Focusing on motor output only, which motor division(s) (and sub-division(s) if applicable) would be affected? (1)

6. On which effector cell types would the adrenergic antagonist work? (2)

7. Name and indicate how the function of one of the effector tissues would be altered by the presence of an adrenergic antagonist. (2)

Answer 1

A.There 5 receptors in total that adrenergic antagonists can act on. they are divided into 2 type- alpha and beta

these are located on lungs, heart, gastro intestinal tract, vascular smooth muscles.

B. Adrenaline, noradrenaline or dopamine

C.β- and α-adrenergic receptors are coupled to different G proteins(G protein coupled receptors) which activates adenylyl cyclase. This leads to increased intracellular cAMP

D.the enzymes catechol-O-methyl transferase (COMT) and monoamine oxidase (MAO) are responsible for degradation of adrenaline into inactive metabolites .COMT is located in the cell body, axons and dendrites of cortical neurons. MAO is found on the outer membrane of mitochondria

F. Adrenergic antagonists work on the cells having adrenergic receptors.