Changes in the level of calcyon mRNA in the brain of rats exposed to cocaine, self-administered or received passively.
The level of mRNA encoding calcyon (measured by in situ hybridization), one of the dopamine receptor interacting proteins, has been examined in the rat brain in the established animal model used to study the mechanisms of cocaine addiction (cocaine self-administration involving a yoked procedure). Two weeks of cocaine self-administration (maintenance) did not affect the level of calcyon mRNA, regardless of the way cocaine was delivered, except for tuberculum olfactorium, where calcyon mRNA was increased after cocaine treatment. In the reinstatement phase of the experiment cocaine alone induced an increase in the calcyon mRNA expression in most of the brain region studied (caudate putamen; tuberculum olfactorium; paraventricular thalamic nucleus; ventromedial hypothalamic nucleus and paraventricular hypothalamic nucleus) but only in the yoked saline control group. In other words, these results show that the single dose of cocaine (10 mg/kg) was able to induce an alteration in the level of calcyon mRNA in these rats which never before experienced any cocaine administration. The most significant effects were observed in the ventromedial hypothalamic nucleus and paraventricular hypothalamic nucleus. Interestingly, a similar effect was observed when the reinstatement of cocaine-seeking behaviour was evoked by cue (conditioned stimuli) that indicates that no cocaine was necessary to induce the changes in the level of calcyon mRNA expression. This effect was significant in tuberculum olfactorium, ventromedial hypothalamic nucleus and paraventricular hypothalamic nucleus. Such a result together with the brain areas involved in these effects might suggest the role of calcyon similar to the CART peptides and special vulnerability of calcyon expression rather to acute than chronic stimuli.
Faron-Górecka
Agata
A
Institute of Pharmacology, Polish Academy of Sciences, 12 Smetna Street, Kraków, Poland.
Gaska
Magdalena
M
Kuśmider
Maciej
M
Frankowska
Małgorzata
M
Adamczyk
Przemysław
P
Filip
Małgorzata
M
Dziedzicka-Wasylewska
Marta
M
D000818:Animals; D001921:Brain / Q000187:drug effects* / Q000378:metabolism*; D003042:Cocaine / Q000008:administration & dosage*; D019970:Cocaine-Related Disorders / Q000378:metabolism*; D003216:Conditioning, Operant; D007275:Injections, Intravenous; D008297:Male; D008565:Membrane Proteins / Q000235:genetics* / Q000378:metabolism*; D012333:RNA, Messenger / Q000378:metabolism*; D051381:Rats; D017208:Rats, Wistar; D012646:Self Administration
D008565:Membrane Proteins; D012333:RNA, Messenger; C405464:calcyon; D003042:Cocaine