Transcript Widely Found and Studied Neurotransmitters

Widely Found and Studied
Neurotransmitters
• Glutamate – has excitatory functions
• 4 Ascending activating systems are very
important
– Cholinergic System uses acetylcholine
– Adrenergic system uses noradrenalin
– Dopaminergic system (actually 2 systems) use
dopamine
– Serotonergic system uses 5-Ht or serotonin
• GABA or gamma-amino butyric acid – has
inhibitory functions
Acetylcholine
• Activate two types of receptors:
– Nicotinic receptors– also stimulated by
nicotine and inactivated or blocked by curare
– Muscarinic receptors– stimulated by
muscurine and blocked by atropine and
scopolamine – use second messenger
Monoamines
• Dopamine – up to 6 types of receptors
– Tyrosine forms L-dopa
– L-dopa synthesized to form dopamine
• Norepinephrine – created by synthesis of
dopamine
• Epinephrine – created from Norepinephrine
• Serotonin (5-Ht) – synthesized from tryptophan
Peptides
• Many types of neuropeptides; two have
been extensively studied
• Sustance P – constriction and dilation of
blood vessels
• Opioid types –
– Endorphins
– enkephalins
How Drugs Work in the Brain
• They work at the level of the synapse
• Agonists
• Antagonists
Possible Drug Actions at the
Synapse
• increase or decrease the synthesis or production of
neurotransmitters
• increase or decrease the ability of the cell to store the chemical in
vesicles
• increase or decrease the amount of transmitter released by vesicles
into the synapse
• it can increase the number and length of time a receptor is open by
increasing or decreasing the production of enzymes that break down
the neurotransmitter
• block or enhance the reuptake and reuse of the neurotransmitter
• Altering the actions of second messegers