Transfer of the discriminative stimulus effects of Δ9-THC and nicotine from one operant response to another in rats.
OBJECTIVE
Transfer of the discriminative stimulus effects of two drugs from one operant (original-response) to a topographically different response (transfer-response) that was spared drug discrimination training was investigated.


METHODS
Eight rats were trained in a counterbalanced one manipulandum (lever press and nose poke) drug discrimination procedure. Counterbalanced IP administered nicotine (0.3 mg/kg) or Δ(9)-tetrahydrocannabinol (3.0 mg/kg) functioned as discriminative stimuli. S(D) drugs occasioned sessions of food-reinforcement (variable-interval 30-s schedule); S(Δ) drugs occasioned non-reinforcement. The original-response (lever-pressing or nose-poking) was initially reinforced during 30-min S(D) drug sessions, and non-reinforced on the other alternating S(Δ)-drug sessions.


RESULTS
Two separate 5-min non-reinforcement tests, counterbalanced by drug order, revealed stimulus control over the original-response by both drugs, which transferred to the transfer-response. Subsequent extinction training of the transfer-response attenuated the original-response response rates with the S(D) drug conditions but had little impact on discriminative control. Discriminative control was reversed for the transfer-response but had little impact on the original-response but, again, reduced response rate.


CONCLUSIONS
These data demonstrate that (a) discriminative control by two distinct drug states can transfer and modulate a topographically different free-operant response and, (b) as is true for exteroceptive stimuli, drug states that function as antecedents embedded within the operant three-term contingency have differing relationships with the response and the primary reinforcer.
Troisi
Joseph R
JR
Department of Psychology, Saint Anselm College, 100 St Anselm Dr, Manchester, NH 03102, USA. jtroisi@anselm.edu
LeMay
Brian J
BJ
Järbe
Torbjörn U C
TU
D000818:Animals; D003216:Conditioning, Operant / Q000187:drug effects*; D004193:Discrimination Learning / Q000187:drug effects*; D013759:Dronabinol / Q000494:pharmacology*; D008297:Male; D009538:Nicotine / Q000494:pharmacology*; D018722:Nicotinic Agonists / Q000494:pharmacology; D011619:Psychotropic Drugs / Q000494:pharmacology; D051381:Rats; D017207:Rats, Sprague-Dawley; D012055:Reinforcement Schedule
D018722:Nicotinic Agonists; D011619:Psychotropic Drugs; D009538:Nicotine; D013759:Dronabinol