Nicotine improves cognitive deficits of dopamine transporter knockout mice without long-term tolerance.
Various studies suggest a dysfunction of nicotinic neurotransmission in schizophrenia and establish that patients suffering from schizophrenia and attention deficit hyperactivity disorder (ADHD) have a high tobacco consumption, potentially for the purpose of self-medication. Owing to its neuroprotective and procognitive effects, transdermal nicotine was proposed to be an effective treatment of some neurodegenerative and psychiatric diseases. Mice deficient in the dopamine transporter (DAT KO) exhibit a phenotype reminiscent of schizophrenia and ADHD, including hyperdopaminergia, hyperactivity, paradoxical calming by methylphenidate and cognitive deficits, some of which being improved by antipsychotic agents. We recently demonstrated that nicotinic receptor content and function were profoundly modified in DAT KO mice. In this study, we assessed the effects of a chronic nicotine treatment in the drinking water on the nicotine-induced locomotion, anxiety status and learning performance. Chronically nicotine-treated DAT KO mice were always hypersensitive to the hypolocomotor effect of nicotine without tolerance and did not exhibit the anxiogenic effect of nicotine treatment observed in WT mice. Very interestingly, both acute and chronic nicotine treatments greatly improved their deficits in the cued and spatial learning, without eliciting tolerance. We speculate that the procognitive effects of nicotine in DAT KO mice are related to the upregulation of alpha7 nicotinic receptors in the hippocampus, amygdala, and prelimbic cortex, all areas involved in cognition. Data from our studies on DAT KO mice shed light on the nicotine self-medication in psychiatric patients and suggest that nicotinic agonists could favorably lead to additional therapy of psychiatric diseases.
Weiss
Stéphanie
S
Inserm, U513, Laboratoire de Neurobiologie et Psychiatrie, University Paris 12, Créteil, France.
Nosten-Bertrand
Marika
M
McIntosh
J Michael
JM
Giros
Bruno
B
Martres
Marie-Pascale
MP
D000704:Analysis of Variance; D000818:Animals; D001345:Autoradiography / Q000379:methods; D001522:Behavior, Animal / Q000187:drug effects; D003072:Cognition Disorders / Q000188:drug therapy* / Q000235:genetics*; D004195:Disease Models, Animal; D050483:Dopamine Plasma Membrane Transport Proteins / Q000172:deficiency*; D004326:Drinking / Q000187:drug effects; D004334:Drug Administration Schedule; D004347:Drug Interactions; D008297:Male; D018782:Maze Learning / Q000187:drug effects; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D009043:Motor Activity / Q000187:drug effects / Q000235:genetics; D009538:Nicotine / Q000008:administration & dosage*; D018722:Nicotinic Agonists / Q000008:administration & dosage*; D018733:Nicotinic Antagonists / Q000008:administration & dosage; D011930:Reaction Time / Q000187:drug effects; D011978:Receptors, Nicotinic / Q000378:metabolism; D013997:Time Factors
D050483:Dopamine Plasma Membrane Transport Proteins; D018722:Nicotinic Agonists; D018733:Nicotinic Antagonists; D011978:Receptors, Nicotinic; D009538:Nicotine