Neuropharmacology

The process by which signaling molecules called neurotransmitters are released from the presynaptic neuron, cross the synaptic cleft, and bind to receptors on the postsynaptic neuron, thereby transmitting a chemical signal between nerve cells.

An agonist is a drug that binds to a receptor and activates it to produce a biological response, while an antagonist binds to a receptor without activating it, blocking the action of endogenous ligands or other agonists.

The quantitative relationship between the dose of a drug administered and the magnitude of the resulting pharmacological effect. It is typically represented as a sigmoidal curve plotting effect against log-dose.

A highly selective semipermeable border of endothelial cells connected by tight junctions that separates circulating blood from the brain extracellular fluid, restricting the passage of most drugs and solutes into the central nervous system.

The ability of synapses to strengthen or weaken over time in response to changes in activity levels. This is the neurobiological basis for learning and memory and a key target for cognitive-enhancing drugs.

A pharmacological mechanism in which a drug blocks the reabsorption of a neurotransmitter back into the presynaptic neuron after it has been released into the synaptic cleft, thereby increasing the neurotransmitter's concentration and duration of action at the synapse.

Pharmacokinetics describes what the body does to a drug (absorption, distribution, metabolism, and excretion), while pharmacodynamics describes what the drug does to the body (mechanism of action, receptor interactions, and downstream effects).

Tolerance is the diminished response to a drug after repeated exposure, requiring increased doses to achieve the same effect. Physical dependence occurs when the body adapts to the drug's presence and withdrawal symptoms emerge upon discontinuation.

The regulation of a receptor's activity by the binding of a modulator at a site distinct from the orthosteric (primary) binding site. Positive allosteric modulators enhance the receptor's response to its natural ligand, while negative allosteric modulators reduce it.

Organized networks of neurons that synthesize, release, and respond to specific neurotransmitters. Major systems include the dopaminergic, serotonergic, noradrenergic, cholinergic, GABAergic, and glutamatergic systems, each regulating distinct physiological and behavioral functions.