What action do sympathomimetic drugs have in the body?

A) Norepinephrine: Norepinephrine is a potent vasoconstrictor primarily used in cases of shock to increase blood pressure by constricting blood vessels. However, it does not have a vasodilatory effect on renal blood vessels. Instead, it tends to decrease renal perfusion due to its strong vasoconstrictor properties, which could worsen renal insufficiency.

B) Dopamine: Dopamine is a catecholamine that has a dose-dependent effect on various receptors. At low doses, dopamine specifically acts on dopaminergic receptors in the kidneys, leading to vasodilation of renal blood vessels, which can improve renal perfusion. This makes it particularly useful in treating shock when there is concern about renal insufficiency or reduced kidney function.

C) Acetylcholine: Acetylcholine is a neurotransmitter of the parasympathetic nervous system, not a catecholamine. It is involved in promoting various physiological effects such as slowing the heart rate and stimulating digestive processes, but it does not have a specific role in vasodilation of renal blood vessels or shock management.

D) Enkephalin: Enkephalins are endogenous peptides involved in the regulation of pain and stress responses. They do not have a direct effect on vasodilation of renal blood vessels. Enkephalins are not typically used to treat shock or manage renal insufficiency.

A) Bradycardia: Bradycardia is a common symptom of a cholinergic crisis. It results from excessive acetylcholine at the neuromuscular junction, which can overstimulate the parasympathetic nervous system, leading to a decrease in heart rate.

B) Rash: A rash is not a typical symptom of a cholinergic crisis. Rash might occur as a side effect of medications or other conditions, but it is not a hallmark feature of a cholinergic crisis in myasthenia gravis.

C) Vomiting: Vomiting is a potential symptom of a cholinergic crisis. It occurs due to the excessive stimulation of the parasympathetic nervous system, which can cause gastrointestinal distress and nausea.

D) Fever: Fever is not typically associated with a cholinergic crisis, but it can occur if there is an underlying infection or other condition. A cholinergic crisis itself usually leads to symptoms like weakness and excessive salivation, not fever.

E) Weakness: Weakness is a hallmark symptom of a cholinergic crisis, as it results from overstimulation at the neuromuscular junction, leading to muscle fatigue and paralysis. This is similar to the symptoms of myasthenia gravis, but in a cholinergic crisis, the weakness is more profound.

F) Drooling: Drooling is another common symptom of a cholinergic crisis. Excessive acetylcholine can lead to excessive salivation due to overstimulation of the parasympathetic nervous system.