Neurotransmitter Physiology

1. Physiology: GABA and NMDA
   1. N-methyl-D-Aspartate (NMDA) receptor
      1. Glutamate binds NMDA receptors and results in excitation
      2. NMDA receptors are up regulated in chronic Alcohol Abuse
      3. NMDA Antagoists include Ketamine
   2. Gamma-aminobutyric acid (GABA) receptor
      1. GABA Agonists bind GABA receptors and resul in inhibition
      2. GABA Receptors are down regulated in chronic Alcohol Abuse
2. Physiology: Neurotransmitter at Synapse
   1. Medications affecting Precursor Uptake
      1. L-Phenylalanine
      2. L-Tyrosine
      3. L-Dopa
      4. Dopamine (DA)
      5. Norepinephrine (NE)
      6. Epinephrine (E)
      7. L-Tryptophan
      8. 5-Hydroxytryptophan,
      9. 5-Hydroxytryptamine (5-HT) = Serotonin
      10. Choline/lecithin + AcetylCoA => Acetylcholine (Ach)
   2. Medications affecting Synthetic Enzymes
      1. Metyrosine (Demser) blocks Tyrosine hydroxylase
         1. Decrease DA, NE, E, 5HT
      2. Methyldopa (Aldomet) blocks decarboxylation
         1. Decrease DA, NE, E, 5HT
   3. Medications affecting Transfer into Vesicle
      1. No clinically available drugs
   4. Medications affecting Vesicle storage
      1. Reserpine (Serpasil) depletes storage
      2. Decreases DA, NE, E, 5HT
   5. Medications affecting Vesicle mobilization
      1. Affects Nerve Impulse Conduction Vesicle release
      2. Electroconvulsive Therapy decreases DA, NE, E, 5HT
   6. Medications affecting Post-synaptic receptors
      1. Reversible receptor blockade by Neuroleptics (Haldol)
   7. Medications affecting Neurotransmitter reuptake
      1. Reuptake inhibition by all Antidepressants (Prozac)
   8. Medications affecting Neurotransmitter breakdown
      1. No drugs available
   9. Medications affecting Neurotransmitter dilution
      1. No drugs available
   10. Medications affecting Neurotransmitter breakdown
       1. Monamine oxidase inhibitor (MOAi) (Parnate, Nardil)
       2. Tacrine Inhibits Acetylcholinesterase
          1. Increases Acetylcholine
3. Physiology: Neurotransmitter Theory applied to Psychiatric Medication
   1. Neuroleptics
      1. Deplete Neurotransmitter Stores
         1. Rauwolfia alkaloids (e.g. Reserpine)
         2. Phenothiazine: Chlorpromazine (Thorazine)
         3. Thioxanthenes: thiothixene (Navane)
         4. Butyrophenones: Haloperidol (Haldol)
      2. Receptor blockade
         1. Lithium Carbonate
         2. Interferes with Neurotransmitter storage Na-K Pump
   2. Stimulants
      1. Mimic neurotransmitter at storage or Receptor sites
         1. Amphetamines: Methamphetamine (Methedrine)
         2. Benzyl-piperidines: Methylphenidate (Ritalin)
   3. Antidepressants: MAO inhibitors
      1. Tranylcypromine (Parnate)
         1. Inactivate MAO
      2. Polycyclic: Imipramine HCl (Tofranil)
         1. Inhibit MAO reuptake