Once infected with HSV, this virus is a part of the body forever. The BBB is a protective mechanism provided primarily by relatively impermeable cappilaries to the brain. Knowing about nts helps us understand some of the effects on our nervous system when chemicals called stimulants or depressants are ingested. Stimulants increase the activity of the CNS by altering the effect of nt at synapses. In contrast to stimulants, depressants often inhibit signal transmission at synapses.
Pesticides work by blocking the action of cholinesterases at the neuromuscular junctions.
The Ach is never broken down and the poor insect dies with its muscles in a state of rigid contractions. B. Depression 1. Serotonin is a nt found in the brain. A decreased level of serotonin and nep in the synaptic cleft is associated with the disorder, depression. Serotonin does affect sleep, mood, attention, and learning.