title: A phosphoinositide-linked dopamine D1 receptor mediates repetitive jaw movements in rats.
abstract: BACKGROUND
  We have demonstrated that rats injected with D1 agonists SKF 38393 or A68930 demonstrate repetitive jaw movements (RJM). These agonist-induced movements in rats are similar in their appearance to those induced in rats by long-term treatment with antipsychotic drugs. Over recent years D-1 receptors were discovered which showed linkage not only to c-AMP but also to PI hydrolysis. We examined the effect of EEDQ inactivation of D1 receptors on D-1 mediated PI hydrolysis and RJM.
  
  
  METHODS
  Twenty four hours following EEDQ or vehicle administration D-1 agonists or vehicle were administered. The number of RJM episodes was assessed in EEDQ and vehicle treated rats. D-1 receptor density and inositol phosphate formation were determined in the striata.
  
  
  RESULTS
  EEDQ administration resulted, 24 hours later, in 70-80% selective depletion of D-1 receptors in the striata but did not modify the rate of RJM induced by D-1 agonists. There was no significant difference in D-1 mediated PI hydrolysis in EEDQ treated rats when compared to vehicle treated group.
  
  
  CONCLUSIONS
  The present data support the earlier demonstration of D-1 agonist induced RJM, an effect mediated by a subpopulation of a D-1 receptor subtype and constitute the first behavioral evidence for the existence of a behavioral response mediated by D-1 like dopamine receptors linked to an alternate second messenger system-PI hydrolysis.
authors.affiliation: Department of Psychiatry, Millhauser Laboratories, New York University School of Medicine, NY 10016, USA.
authors.forename: H
authors.initials: H
authors.lastname: Rosengarten
authors.forename: A J
authors.initials: AJ
authors.lastname: Friedhoff
mesh_terms: D000818:Animals; D001522:Behavior, Animal / Q000187:drug effects; D007568:Jaw / Q000187:drug effects* / Q000502:physiology*; D008297:Male; D009068:Movement / Q000187:drug effects* / Q000502:physiology*; D010716:Phosphatidylinositols / Q000494:pharmacology*; D051381:Rats; D017207:Rats, Sprague-Dawley; D017447:Receptors, Dopamine D1 / Q000187:drug effects*
chemical_list: D010716:Phosphatidylinositols; D017447:Receptors, Dopamine D1