The interaction between the neuromodulator adenosine and adenosine receptors on the surface of neurons modifies the neurons’ responses to neurotransmitters. The activated adenosine receptors alter the levels of small signaling molecules (i.e., second messengers) in the cells. Depending on the receptors and cells involved, these changes can make it easier or more difficult for neurotransmitters ...

Excitatory neurotransmitters, the most important of which is glutamate, increase the activity of signalreceiving neurons and play a major role in controlling brain function. Glutamate exerts its effects on cells in part through three types of receptors that, when activated, allow the flow of positively charged ions into the cell. Of these, the N-methyl-D-aspartate (NMDA) receptor plays a partic...

Serotonin is an important brain chemical that acts as a neurotransmitter to communicate information among nerve cells. Serotonin’s actions have been linked to alcohol’s effects on the brain and to alcohol abuse. Alcoholics and experimental animals that consume large quantities of alcohol show evidence of differences in brain serotonin levels compared with nonalcoholics. Both shortand long-term ...

The nervous system is composed of networks of cells that engage in coordinated circuits to permit neural function. Within these precise neural circuits, communication between individual cells is primarily chemical in nature. Neurotransmitter release via exocytosis of neurotransmitter-filled synaptic vesicles is a fundamental step in this process. Here we overview the biochemical processes that ...

Neurotransmitters are released into the extracellular space during synaptic transmission. The actions of these chemical signals are terminated through active uptake by transporters that are located in the plasma membrane of neurons and glial cells. Transporters harness electrochemical gradients to force the movement of transmitter back into cells against its concentration gradient. These protei...