Alcohol Drugs and Behavior Lecture - October 24th, 2003

Janelle is lecturing....

The tolerance in the use of stimulants.

Acute tolerance - there is some tolerance on the first administration of
any drug...


blood content of drug.
I
I
I
I
I	X
I   X		X
I			X
IX				X
I					X
IA					B
I
I
I_______________________________________
    Time

Here the physical results would be slightly different than the graph would 
indicate. (Based on blood content) The effect at A on behavior and feeling
a high would be much greater than at B even though the levels are very
similar.

Coke Run - when users try to take the drug over and over when the reach
the lows so as to reach the highs.

However in this scenario... Tolerance(acute) cuases these subsequent
doses to effect less and less. (After a while the rush is gone. after
another period of use even the mood effects are gone.)

Sensitization occurs whith this drug as well... however it only applies to
the bad effects of the drug. (In essence it enhances only the letdown
phase effects.)

Coke out = only bad effects (usually when people end the coke run)
(Usual end of cocaine run is loss of all funds to buy it!)

Animals that become addicted to cocaine will work extremely hard to get it!
(this is also true with people )

the experiment used to prove this is called a break point experiment.




I		      I
I		      I  A rat is in this box...
I		      I (We have a rat=x with a cathiter attachted to the 
I		      I jugular vein... this is the method of administration
I______________X______I of the cocaine.) A rat can press the lever to get
			an administration of the drug.

A ratio method is used (so if a rat pressed the lever the next time he needs
to press it perhaps twice as many times and it increases like that on to
the break point)

The break point is where the rat will not press the lever anymore to get
the stimulation.

The test results of this experiment would look something like this....

(This test would be for non pre experienced users of the drug)
Break Point           W= Water(saline) G= glucose(sugar water) C= cocaine

I
I		X
I
I
I
I          X
I
I
I      X
I  X
I
I_________________________
   W   G   C    C(addicts)
      
  	Condition

Another experiment that shows the motivation to get the drug...
(Same apparatus used but now to press the lever the rats will be shocked)
The rats will still press the lever even though they will be shocked as well.

Tolerance and drug effects are experienced at different times...
this tells us that these things are produced by different mechanisms of the
brain. (Like how the phases arrive at different times rush-euphoria-letdown
and then the tolerance is building up acutely as well.)


Tolerance's primary mechanism is "Receptor Down Regulation" 
(where less receptors exist due to the fact that the body kills them)

VTA ----> NACC              This is a reward. But now there aren't as many
    Dopamine Projection.    receptors.

this means nothing you do will bring you as much joy or pleasure as it
used to becuase many of the reward system's receptors have been killed.

Crack Babies....
(not so bad that they will never learn or never be normal)
In general the belief currently is that a crack addicted mother
will not get pre-natal care. (this could contribute to the low
weight of the babies.) These babies are also a great deal "fussier"
so these babies combined with mothers who are busy doing crack
is a very poor one. (They don't believe the baby's fussyness is related
to drug withdrawals.)

That's all folks.