Narcotics research, rehabilitation, and treatment. Hearings, Ninety ...

490In the lower two graphs are ilhistrated experiments in which theanimal ^^ as taking codeine alone, to your left, in which he made abouta thousand bar presses to get 30 injections of codeine, and then hisbehavior in 1 day in which he was pretreated with an injection ofnaloxone. When he was pre treated with naloxone he bar pressed afew times, about 50 times, and quit immediately. There was no morebar pressing in spite of the fact the drug was available to him.Mr. Brasco. Doctor, naloxone is not a substance upon which onebecomes dependent?Dr. ViLLARREAL. That is correct.Mr. Brasco. In the case of this monkey, after he was given a doseof naloxone, he did not bar press.Dr. ViLLARREAL. That is right.Mr. Brasco. Now, how did he come to bar press again when youtook the naloxone away? I do not understand that. If you are notdependent on naloxone it would seem to me that that would be asuccessful treatment for taking someone off drugs and havmg themdrug free. I do not get the relationship of his bar pressing again.Dr. ViLLARREAL. Perhaps I can answer jour question this way.When the animal is switched from any drug to an inert substance, tosaline, just physiological solution, the animal quits bar pressing. Andwhat we have done with the pre treatment of naloxone is to rendercodeine totally ineffective so that the self-injections of codeine arelike self-injections of physiological saline. There is no longer an Althingm the syringe.Mr. Brasco. So, he does not bar press at all.Dr. ViLLARREAL. He probes a little bit as you saw at the beginningof the session, because he has all this drive but when there is noeffect, he quits.Mr. Brasco. Then, how does he go back to bar pressing again,because the apparatus gives him another shot of an addictive substanceor does he do that by accident?Dr. ViLLARREAL. He will do that by accident or by the strength ofthe habit of bar pressing behavior.[Slide]Dr. ViLLARREAL. These few slides that come next mil get to thepoint I think you are driving at. These are graphs of successive daA'sin which the monkej s are taking codeine. The}' are taking about 60injections a day. The monkey takes about 65, 58, 52, and so on,injections a day. This goes on for months and months.On this day we treat him with naloxone and he quits. He quits for2 days. Only on the first day he got naloxone. But then a little bit ofexploration, a little bit of probing on the bar, brings him back toexperience the full effects of codeine. So, as codeine is available againhe goes back to the previous behavioral base line.Mr. Brasco. The point is this. After the naloxone treatment hestill has the physiological urge for the drug.Dr. ViLLARREAL. YcS.Mr. Brasco. So than naloxone would be something that would haveto be given steadily also.Dr. ViLLARREAL. That is right.Mr. Brasco. As methadone.