A student ask the pharmacology instructor to describe the function of cholinergic agonist. What would be the instructor's reply?

A) Increased intraocular pressure: Sympathomimetic drugs stimulate the sympathetic nervous system and promote "fight or flight" responses, often resulting in vasoconstriction and other effects. Some sympathomimetics, especially those that affect alpha-adrenergic receptors, can lead to increased intraocular pressure, which is a concern in conditions like glaucoma.

B) Decreased blood pressure: Sympathomimetic drugs generally increase blood pressure by stimulating alpha and beta receptors that cause vasoconstriction and increased heart rate. In contrast, drugs that would decrease blood pressure are usually parasympathomimetics or other agents designed to block sympathetic responses.

C) Decreased heart rate: Sympathomimetic drugs typically increase heart rate by stimulating beta-1 adrenergic receptors in the heart. These drugs are used in situations requiring increased cardiac output or to counteract bradycardia. Decreased heart rate would typically occur with parasympathomimetic drugs or medications that block sympathetic activity (e.g., beta blockers).

D) Increased respiration: Sympathomimetic drugs can increase respiratory rate by promoting bronchodilation through beta-2 adrenergic receptor activation in the lungs. However, "increased respiration" as a general effect is not as specific or consistent as the other cardiovascular and ocular effects of these drugs. The primary and most prominent physiological change would be related to the cardiovascular effects.

A) Parkinson disease is characterized by an imbalance of dopamine and acetylcholine:
The decrease in dopamine results in an imbalance between dopamine and acetylcholine. Normally, dopamine and acetylcholine work in a balanced manner to regulate motor control. As dopamine levels decrease in Parkinson's disease, acetylcholine's effects become more prominent, leading to motor symptoms such as tremors, rigidity, and bradykinesia (slowness of movement).

B) Parkinson disease involves increased dopamine production and decreased acetylcholine:
This statement is incorrect. In Parkinson's disease, there is actually a decrease in dopamine production, not an increase. The disease is characterized by the degeneration of dopamine-producing neurons, leading to the motor symptoms typical of Parkinsonism. The imbalance in Parkinson's disease is primarily one of decreased dopamine and relatively increased acetylcholine activity.

C) Alzheimer disease is caused by decreased amounts of dopamine and degeneration of cholinergic neurons:
While Alzheimer's disease does involve a degeneration of cholinergic neurons (specifically those that release acetylcholine), the primary pathology is related to the accumulation of amyloid plaques and tau tangles, not primarily a decrease in dopamine. Alzheimer's disease is primarily associated with a deficiency in acetylcholine, not dopamine, leading to cognitive impairments, rather than motor deficits.

D) Alzheimer disease involves a possible excess of acetylcholine and neuritic plaques:
This statement is incorrect. Alzheimer's disease is characterized by a deficiency of acetylcholine, which plays a crucial role in memory and cognitive function. The hallmark pathologic features of Alzheimer's disease include the presence of neuritic plaques (formed from amyloid beta) and neurofibrillary tangles (composed of tau protein), not an excess of acetylcholine.