Yes
Mechanism of action Edit
Varenicline displays full agonism on α7 nicotinic acetylcholine receptors and is a partial agonist on the α4β2, α3β4, and α6β2 subtypes.[25][26][27] In addition, it is a weak agonist on the α3β2 containing receptors.
Varenicline's partial agonism on the α4β2 receptors rather than nicotine's full agonism produces less effect of dopamine release than nicotine's. This α4β2 competitive binding reduces the ability of nicotine to bind and stimulate the mesolimbic dopamine system - similar to the method of action of buprenorphine in the treatment of opioid addiction.[3] (source wiki)
Basically, the primary cause of nicotine causing pleasure involves a4b2 nicotinic acetylcholine receptors (nACh) .
Both chantix and nicotine can fit into the nACH a4b2 receptors in your brain but nicotine is much better at fully activating the receptor.
The result is when you take chantix is may be easier to quit smoking because it goes in and clogs up the a4b2 nACh receptors so that when you smoke the nicotine can't fit into the receptors as effectively reducting the reinforcing effects of nicotine.
However, a4b2 nACh play a important role in dopamine release in a part of the brain called the mesolimbic brain areas. Additionally nicotine receptors are widely expressed in the parts of the brain involved in focus and memory. Additionally, muscarinic acetylcholine receptors a additional target of nicotine may play a important role in learning associations between a positive stimulus (amphetamine) and learning to go where that stimulus is. Rats where the muscarinic acetylcholine receptors are blocked by scopolamine impair learning to go to the right spot that has something positive or avoid a side that delivers a shock.
Basically, nicotine has many mechanisms that enhance the subjective effects of amphetamines
Some but not all of the reasons may include
A. Increased dopamine signaling in the mesolimbic brain. Areas associated with reward
B. Muscarinic acetylcholine agonism which may play a important role in learning to decrease or increase behaviors based on positive or negative outcomes.
C. At low doses increased noradrenaline release increasing the rush and causing activity in the locus coeroleus important for wakefulness
D. Increased focus due to changes in the frontal part of your brain.
E. Increased short memory due to partly changes In the hippocampus