PS268 Chapter Notes - Chapter 4: Tegmentum, Nucleus Basalis Of Meynert, Pituitary Gland
Chemical Pathways
-neurotransmitters associated w actions of psychoactive drugs include dopamine,
acetylcholine, norepinephrine, serotonin, GABA, glutamate, and endorphins
-we think of many psychoactive drug actions in terms of a drug's effect on one of these
chemical pathways
-malfunctions of neurotransmitter systems lead to disease states, which can be effectively
treated w drugs that target the affected system
Dopamine:
Pathway 1) and 2)
-cells form the mesolimbic dopamine pathway and medocortical pathway mediate
some types of psychotic behaviour
-cells in nucleus accumbens receive input from dopamine fibres in ventral tegmental
area in midbrain
-overaction of dopamine in these pathways produces hallucinations, weakened by
dopamine blocking drugs
-most prominent neurochemical theory of drug abuse is based on idea that all rewarding
drugs stimulate dopamine neurons in mesolimbic pathway and stimulation of this reward
system tells rest of brain “that's good, do it again” but recent data suggests this view of
overly simplistic
Pathway 3)
Document Summary
Neurotransmitters associated w actions of psychoactive drugs include dopamine, acetylcholine, norepinephrine, serotonin, gaba, glutamate, and endorphins. We think of many psychoactive drug actions in terms of a drug"s effect on one of these chemical pathways. Malfunctions of neurotransmitter systems lead to disease states, which can be effectively treated w drugs that target the affected system. Cells form the mesolimbic dopamine pathway and medocortical pathway mediate some types of psychotic behaviour. Cells in nucleus accumbens receive input from dopamine fibres in ventral tegmental area in midbrain. Overaction of dopamine in these pathways produces hallucinations, weakened by dopamine blocking drugs. Nigrostriatal dopamine pathway: cells from substania nigra go past hypothalamus and end in basal ganglia (in corpus striatum) to form this pathway, loss of cells = parkinson"s. Parkinson"s is a dopamine deficiency disorder thus most popular treatment is dopamine precursor l-dopa which, once in brain, is rapidly converted to dopamine restoring concentrations. Dopamine itself does not readily cross blood-brain barrier.
