Neuropharmacology

• One common class of drugs alters how neurotransmitters are cleared from the synaptic cleft
• Serotonin Selective Reuptake Inhibitors (SSRIs) are drugs that inhibit the function of the reuptake transporter found in synapses that release the neurotransmitter serotonin
• Reuptake transporters are proteins that bind to neurotransmitters and remove them from the synaptic cleft
• Some examples of SSRIs are Prozac and Zoloft, which both treat mood disorders
• Drugs usually impact neurotransmitters in one of two ways: as an agonist or antagonist
• An agonist is a drug that enhances the activity of a neurotransmitter
• Agonist drugs often mimic the action of the endogenous neurotransmitter it binds to
• Endogenous means naturally occurring
• Competitive agonists compete for the same binding site with the endogenous neurotransmitter
• For competitive agonists to be effective, they usually need to be more concentrated than the endogenous neurotransmitter
• Noncompetitive agonists are also called allosteric modulators
• Noncompetitive agonists can increase the activity of the neurotransmitter without blocking its binding site
• Partial agonists compete for the same binding site, but have a smaller physiological effect on the postsynaptic receptor than the usual neurotransmitter
• An antagonist drug decreases or even fully blocks the activity of the neurotransmitter
• Antagonist drugs work to prevent the binding or the action of the endogenous neurotransmitter
• Competitive antagonists block the binding site of a receptor
• Noncompetitive antagonists bind at a different site than the endogenous neurotransmitter, which in turn changes the shape of the receptor to decrease the effect of the usual neurotransmitter
• An allosteric site is a site on a protein that can be modified by a second molecule (Where noncompetitive antagonists go)
• L-DOPA is an agonist that is used to treat Parkinson's disease
• Parkinson's disease involves the death of dopamine-producing neurons in the basal ganglia
• L-DOPA increases the amount of dopamine in the neurons of the brain