What are the different ways in which a drug could act as an

What are the different ways in which a drug could act as an agonist or an antagonist (neurotransmitter)?

Solution

There are many ways a drug can control the synapse but the main mode of action is through whether the drug is increasing the activity of neurotransmitter (agonist) or inhibiting the activity of neurotransmitter (antagonist)

Agonist mimic the action of naturally occuring neurotransmitters with 2 main types direct agonist which directly binds and activates the neurotransmitter and indirect agonist which binds and anhances the activity of neurotransmitter. examples include apomorphine (direct) and cocaine (indirect)

antagonists are drugs that bind and inhibit the activity of neurotransmitter, there are 2 main types again direct acting which binds to the same receptor as agonist but block the activity (egs haloperidol which is a competitive antagonist). under direct acting antagonists 2 main types include competitive antagonists which cometes with agonist for the bining site and non competitive antagonists binds irreversibly to the same agonist site

Another class indirect acting antagonist inhibits the synthesis of neurotransmitter (synthesis inhibitor egs. alpha methyl-para-tyrosine) or inhibits synaptic storage of neurotransmitter (egs. reserpine)