Psychiatric Drugs and Medications Q 20

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A side effect of cholinergic administration is:

  

     A. Nausea

     B. Diarrhea

     C. Increase salivation

     D. All of the above

    

    

Correct Answer: D. All of the above

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Cholinergic drugs increase GI activity, causing all of these side effects. Acetylcholine is a major neurotransmitter in the body. Depending on the type of receptors through which it undergoes mediation, the peripheral actions of acetylcholine classify as working on muscarinic (M1, M2, M3, M4, M5) or nicotinic (Nm, Nn) receptors. M1 receptors are present on the gastric parietal cells and in the central nervous system. M2 receptors are present on the heart, visceral smooth muscle. M3 receptors on the smooth muscle, exocrine glands, and receptors of the bladder. Nicotinic receptors are present in the central nervous system, adrenal medulla, autonomic ganglia, and neuromuscular junction.

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Option A: The peripheral nervous system consists of the autonomic and the somatic nervous system. The autonomic nervous system can be further broken down into sympathetic and parasympathetic nervous systems. The parasympathetic nervous system regulates various organ and gland functions and primarily uses acetylcholine as its primary neurotransmitter, as do all the cholinomimetics.

Option B: The contraction of the smooth muscle in various organs of the body gets mediated through M3 receptors. Tone and peristalsis in the gastrointestinal tract increase and sphincters relax, causing abdominal cramps and evacuation of the bowel.

Option C: Secretions from glands are increased through the M3 and M2 receptors, resulting in salivation, sweating, lacrimation, gastric, and tracheobronchial secretions.

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