title: Involvement of dorsolateral periaqueductal gray cholecystokinin-2 receptors in the regulation of a panic-related behavior in rats.
abstract: Cholecystokinin (CCK) has been implicated in anxiety disorders. The midbrain periaqueductal gray (PAG), which modulates anxiety and panic reactions, contains CCK-immunoreactive fibers and CCK(2) receptors. The present study investigated the involvement of CCK(2) receptors of the PAG dorsolateral subdivision (dlPAG) in the regulation of inhibitory avoidance and escape, two defensive behaviors that have been related in terms of psychopathology to generalized-anxiety and panic disorders, respectively. Male Wistar rats were microinjected in the dlPAG with the CCK(2) receptor agonist cholecystokinin-tetrapeptide (CCK-4; 0.08-0.32 nmol/0.2 microL), the CCK(2) receptor antagonist LY-225910 (0.05-0.20 nmol/0.2 microL) or LY-225910 prior to CCK-4. Inhibitory avoidance and escape behaviors were evaluated in the elevated T-maze. Whereas CCK-4 facilitated escape, indicating a panic-like action, LY-225910 had the opposite effect. Pretreatment with a non-effective dose of LY-225910 prevented the panic-eliciting action of CCK-4. Neither CCK-4 nor LY-225910 affected inhibitory avoidance acquisition. The present results substantiate the view that dlPAG CCK(2) receptors modulate panic-related behaviors.
authors.affiliation: Department of Pharmacology, School of Medicine, University of São Paulo, Av. Bandeirantes 3900, Ribeirão Preto, SP 14049-900, Brazil. lejobe@usp.br
authors.forename: Leandro José
authors.initials: LJ
authors.lastname: Bertoglio
authors.forename: Hélio
authors.initials: H
authors.lastname: Zangrossi
mesh_terms: D000818:Animals; D001362:Avoidance Learning / Q000187:drug effects / Q000502:physiology; D001522:Behavior, Animal / Q000187:drug effects / Q000502:physiology; D002766:Cholecystokinin / Q000378:metabolism*; D004195:Disease Models, Animal; D005106:Exploratory Behavior / Q000187:drug effects / Q000502:physiology; D005239:Fear / Q000187:drug effects / Q000502:physiology; D008297:Male; D018782:Maze Learning / Q000187:drug effects / Q000502:physiology; D009043:Motor Activity / Q000187:drug effects / Q000502:physiology; D009434:Neural Pathways / Q000187:drug effects / Q000378:metabolism*; D016584:Panic Disorder / Q000139:chemically induced / Q000378:metabolism* / Q000503:physiopathology; D010487:Periaqueductal Gray / Q000187:drug effects / Q000378:metabolism*; D011799:Quinazolines / Q000494:pharmacology; D052999:Quinazolinones; D051381:Rats; D017208:Rats, Wistar; D043887:Receptor, Cholecystokinin B / Q000819:agonists / Q000037:antagonists & inhibitors / Q000378:metabolism*; D013758:Tetragastrin / Q000494:pharmacology
chemical_list: C435663:2-(2-(5-bromo-1H-indol-3-yl)ethyl)-3-(1-methylethoxyphenyl)-4-(3H)-quinazolinone; D011799:Quinazolines; D052999:Quinazolinones; D043887:Receptor, Cholecystokinin B; D013758:Tetragastrin; D002766:Cholecystokinin