Question

What do phosphodiesterase inhibitors do to cAMP?

In regards to B-1 and B-2, what do PDEIs do?
a) Increase cAMP levels; Enhance B-1 and B-2 receptor activation
b) Decrease cAMP levels; Inhibit B-1 and B-2 receptor activation
c) Convert cAMP to cGMP; Have no effect on B-1 and B-2 receptors
d) Hydrolyze cAMP; Enhance B-1 but inhibit B-2 receptor activation

Answer 1

Phosphodiesterase inhibitors prevent the breakdown of cAMP by phosphodiesterase, therefore leading to increased cAMP levels and enhanced activation of Beta-1 and Beta-2 receptor signaling pathways.

Step-by-step explanation:

Phosphodiesterase inhibitors (PDEIs) interact with the signaling pathways within cells, specifically affecting the molecule cyclic AMP (cAMP). cAMP is an important secondary messenger that is formed from ATP by the action of the enzyme adenylyl cyclase, and is involved in the activation of protein kinases during the phosphorylation cascade.

When a PDEI is introduced, it inhibits the enzyme phosphodiesterase, which is responsible for deactivating and degrading cAMP. As a result, the levels of cAMP increase because it is not being broken down as rapidly. This elevation in cAMP levels enhances the activation of signaling pathways downstream of both Beta-1 (B-1) and Beta-2 (B-2) receptors, as these pathways are dependent on the presence of cAMP to activate protein kinases and further trigger cellular responses.