Question

A patient of yours is experiencing sustained muscular contractions as a side effect of a drug. They are injected with another drug that stops nerves from firing action potentials, but the contractions continue. What does this tell you about the cause/source of this patient’s sustained contractions?

Answer 1

The cause of patients sustained muscular contraction can be due to the side effects of drug which the patient was taking. The drug has inhibited the acetylcholinesterase due to which acetylcholine is not getting hydrolysed into choline and acetate and concentration of acetylcholine is remaining high at neuromuscular junction which is increasing the duration and strength of muscular contractions eventhough the action potential has stopped due to the action of other drug given to the patient. Acetylcholinesterase is an enzyme which is present at neuromuscular junction and it's function is to stop the synaptic transmission of impulses by breaking down acetylcholine into choline and acetate and thus stops muscles contraction. The side effect of drug has inhibited acetylcholinesterase at the neuromuscular junction and due to which acetylcholine is not broken down which is continuing the muscle contraction.