Cross-sensitization between footshock stress and apomorphine on self-injurious behavior and neostriatal catecholamines in a rat model of Lesch-Nyhan syndrome.

Abstract

The effects of footshock sensitization (priming), apomorphine (APO) priming and their combination on behavior and neostriatal and cortical catecholamines were examined in adult rats which had neonatally received bilateral intracerebroventricular injections with 6-hydroxydopamine (6-OHDA; a model of Lesch-Nyhan syndrome (LNS)) or vehicle (unlesioned rats). Lesioned (6-OHDA-treated) rats displayed self-biting (SB; 7/20 rats) and self-injurious behavior (SIB; 1/20 rats) during APO priming, but not during footshock priming. During subsequent acute cumulative APO dosing, 20-30% of lesioned rats primed with APO alone or footshock alone displayed SB and SIB. However, SB and SIB incidence in APO+footshock-primed lesioned rats was nearly tripled. Dopamine (DA) synthesis, metabolism and extracellular concentrations (disposition) in unlesioned rats and in cortices of lesioned animals were unaffected by priming. In lesioned rats primed with APO alone or footshock alone, only neostriatal 3-methoxytyramine (3-MT) was significantly increased. However, neostriatal DA and metabolite concentrations (and norepinephrine (NE)) were all significantly elevated in lesioned rats primed with both APO and footshock. These results confirm that neonatal 6-OHDA-induced neostriatal catecholamine depletion can be antagonized by experiential change, suggest that behavioral and neurochemical cross-sensitization between APO and footshock in such rats is unidirectional and support the view that stress can exacerbate the incidence of SIB in LNS.

• Authors: C J Stodgell, P S Loupe, S R Schroeder, R E Tessel
• Journal: Brain research (Brain Res) Vol. 783 Issue 1 Pg. 10-8 (Feb 02 1998) ISSN: 0006-8993 [Print] Netherlands
• PMID: 9479035 (Publication Type: Journal Article, Research Support, U.S. Gov't, P.H.S.)

Chemical References

• Catecholamines
• Dopamine Agonists
• Neurotoxins
• Oxidopamine
• Apomorphine

Topics

• Animals
• Animals, Newborn
• Apomorphine (pharmacology)
• Catecholamines (metabolism)
• Disease Models, Animal
• Dopamine Agonists (pharmacology)
• Electroshock
• Injections, Intraventricular
• Lesch-Nyhan Syndrome (chemically induced, metabolism, psychology)
• Male
• Neostriatum (drug effects, metabolism)
• Neurotoxins
• Oxidopamine
• Rats
• Rats, Sprague-Dawley
• Self-Injurious Behavior
• Stress, Physiological (metabolism, psychology)