Effects of hypophysectomy on compulsive checking and cortical dendrites in an animal model of obsessive-compulsive disorder.
Hormones may modulate the symptoms of obsessive-compulsive disorder (OCD), but the evidence is equivocal and not consistent across studies, with findings of hormone-associated increases and decreases of symptoms. To assess whether a strong endocrine influence on OCD exists, the effects of hypophysectomy were examined in an animal model of OCD. The model involves repeated injections of the dopamine D2/D3 receptor agonist, quinpirole, to induce locomotor sensitization and compulsive checking behavior. Intact and hypophysectomized rats were administered quinpirole (0.5 mg/kg x 6, twice weekly) or saline and compulsive checking in a large open field was measured according to a standard protocol. Results showed that in hypophysectomized animals, the development of locomotor sensitization was attenuated but the expression of quinpirole-induced compulsive checking was full-blown. Analysis of Golgi-stained neurons showed changes in spine density in Cg3 and Par1 and increased branching of apical dendrites in Cg3. It is suggested that compulsive checking could be coupled with drug-induced increases in Cg3 dendritic branching and that changes in spine density may reflect a compensatory adjustment in dopamine-innervated regions. On the basis of the animal model findings, it is concluded that the presence of OCD checking compulsions is not dependent on pituitary axis hormones.
Dvorkin
Anna
A
Department of Zoology, Tel-Aviv University, Tel-Aviv, Israel.
Culver
Kirsten E
KE
Waxman
Donna
D
Szechtman
Henry
H
Kolb
Bryan
B
D000818:Animals; D001522:Behavior, Animal / Q000187:drug effects; D002540:Cerebral Cortex / Q000187:drug effects* / Q000473:pathology; D003192:Compulsive Behavior / Q000139:chemically induced / Q000523:psychology*; D003712:Dendrites / Q000187:drug effects* / Q000473:pathology; D004195:Disease Models, Animal; D007016:Hypophysectomy; D007279:Injections, Subcutaneous; D008297:Male; D009043:Motor Activity / Q000187:drug effects; D009473:Neuronal Plasticity; D009771:Obsessive-Compulsive Disorder / Q000139:chemically induced / Q000473:pathology* / Q000523:psychology*; D010907:Pituitary Hormones / Q000502:physiology*; D019257:Quinpirole; D051381:Rats; D020318:Rats, Long-Evans; D017448:Receptors, Dopamine D2 / Q000819:agonists; D050637:Receptors, Dopamine D3 / Q000819:agonists
D010907:Pituitary Hormones; D017448:Receptors, Dopamine D2; D050637:Receptors, Dopamine D3; D019257:Quinpirole