Final answer:
Tamsulosin is the correct answer as it is an alpha-adrenergic receptor blocker that relaxes the bladder neck and prostate smooth muscle. Angiotensin II is a vasoconstrictor, nicotinic receptors are involved in affecting both divisions of the autonomic system, and acetylcholine leads to pupil constriction.
Step-by-step explanation:
Among the options given, Tamsulosin is an alpha-adrenergic receptor blocker that relaxes the bladder neck and prostate smooth muscle. Alpha1-adrenergic receptors, which are part of the G protein-coupled receptor superfamily, play a role in smooth muscle contraction when activated. Blockage of these receptors by tamsulosin leads to relaxation of smooth muscle, which can help with conditions like benign prostatic hyperplasia. Conversely, Finasteride is a 5-alpha reductase inhibitor affecting hormone levels, Atenolol is a beta-blocker affecting the heart, and Lisinopril is an ACE inhibitor affecting blood pressure.
Angiotensin II is a vasoconstrictor among the options, whereas nitric oxide causes vasodilation. A drug that affects both divisions of the autonomic system would likely bind to nicotinic receptors.
Beta-blockers, such as Atenolol, bind to G-protein-linked receptors in heart muscles, blocking adrenaline, reducing heart rate, and lowering blood pressure. Lastly, acetylcholine results in the constriction of the pupil, and progesterone can bind to receptors affecting water retention, similar to aldosterone. For urination, the external urethral sphincter must be inhibited by somatic motor neurons.