Effects of drugs in the synaptic gap

IMPORTANT NOTE: most of this information was collected form the Physician's Desk Reference.  It is to be used for general understanding, not as medical advice.

Reduce Firing

1. Block Release

2. Block Receptors

Increase Firing

1. Block Re-Uptake

2. Block Enzyme from

breaking down NT

3. Open Membrane

4. Make Cell Produce More NT

Increase, then Decrease Firing

1. Mimic Drug, Eventually

Brain Produces Less NT

EFFECTS OF DRUGS IN THE SYNAPTIC GAP

(in progress)
  • Effect in Synaptic Gap
Drug Name Neurotransmitters affected Disorder for which drug is used Areas of the brain most affected
Reduce Firing        
  • 1. Block Release
alcohol

(also inhibits ACh)

 blocks release of NT that inhibits dopamine (more Dopamine)    
  • 2. Block Receptors
Librium, Valium, et al GABA (anxiety)  
  Thorazine et al dopamine (schizophrenia) (in theory)  
  Oculinum acetylcholine dystonia (strabismus)  
  • blocks receptor sites (that are on the pre-synaptic side)
  • (reduces adenosine, increases main)
caffeine (indirectly thorugh adenosine)

norepinephrine, dopamine, acetylcholine

    
not sure which barbituates (e.g. anesthesia, phenobarbital) norepinephrine    
  serentil adrenaline (in RAS) schizophrenia (in RAS)
Increase Firing        
  • 1. Block Re-Uptake
tricyclics (tofranil, endep, anafranil) norepinephrine, serotonin depression  
  Prozac serotonin Depression, a whole host of other things (e.g. obsessive compulsive)  
  • Block Reuptake
cocaine norepinephrine, dopamine, serotonin    
  • 2. Block Enzyme from breaking down NT
MAO Inhibitors norepinephrine, dopamine ?? (depression)  
  tricyclics also do this dopamine (depression)  
  • 3. Attach to NT vesicles,causing them to release more NT
amphetamines norepinephrine, dopamine    
  • 3. Open Membrane
       
  • 4. Make Cell Produce More NT
       
         
Increase, then Decrease Firing        
  • 1. Mimic Drug, Eventually Brain Produces Less NT
  • (increases dopamine by decreasing effect of NT that inhibits dopamine)
morphine, heroin endorphins

(endorphins block cell that blocks the release of dopamine)

   lots of receptors in limbic system, also throughout brain & spinal cord
  • Mimics drug
nicotene one set of acetylcholine receptors called "nicotene receptors" that trigger epinephrine from adrenal glands and dopamine & serotonin   in limbic system
  • 2 effects
  • 1. blocks release of NT that inhibits dopamine (more Dopamine)
  • 2. inhibits release of ACh (how?)
alcohol dopamine,

acetylcholine

    
  • marijuana
      substantia nigra, part of the dopamine production system

Tolerance

Post-synpatic neurons can change the number of receptors they have for a drug, or the sensitivity to the drug

Also, liver can metabolize drug quicker, so less of it in system

Questions:

alcohol, speed

Nicotene increases acetylcholine

amphetimines similar to norepinephrine (Mimics?)

(incl. Ritalin)

cocaine increases norepinephrine

LSD decreases serotonin ( a link)

PCP

mescaline, cannabis