Hydroxy Amphetamine Case Study

In this case the man suffers from a sympathetic preganglionic lesion, and the neurotransmitter needed in order to communicate with the postganglionic neuron is Ach. (12) To create an excitatory response in the cholinergic-nicotinic receptor without having the neuron release the neurotransmitter, doctors can administer a nicotinic agonist in order to make the transmission of the signal possible. The nicotinic drug will mimic the action of Ach. (5,13) Unfortunately, recreating Ach action could create further problems, because these medical drugs might also stimulate the receptors of the parasympathetic division. Therefore, acting on the third order neuron through the administration of adrenergic agonists would be the smartest choice, even though the lesion is found in the second order neuron.
Hydroxy amphetamine can be instead administrated for anisocoria management. In fact, agents containing amphetamine are capable of releasing norepinephrine and therefore act in the third order neuron synaptic cleft and recreate the sympathetic process. (14)
Another way to alleviate symptoms is administering parasympathomimetic antagonist drugs, which inhibit the parasympathetic processes favoring the sympathetic ones.
For example, contraction of the smooth circular muscle of the iris can be stimulated by administration of a muscarinic receptor antagonist, such as atropine. This drug will prevent parasympathetic action, thus providing an increase in the diameter of the pupil.