title: Intranigral infusion of enkephalins elicits dyskinetic biting in rats.
abstract: Leu- and Metenkephalin (Lenk and Menk) and their more stable analogues D-Ala-Leu- and D-Ala-Metenkephalin (DALenk and DAMenk) as well as D-Ala-D-Leu- and D-Ala-D-Metenkephalin (DADLenk and DADMenk) were infused bilaterally into substantia nigra in awake rats and oral movements were recorded for 90 min. DADLenk and DADMenk elicited dose-dependent biting dyskinesias with a chewing rate of about 90 jaw movements/min. DALenk produced a similar but weaker effect, whereas DAMenk, Lenk and Menk were ineffective in the doses given. These findings suggest a possible enkephalinergic mechanism underlying neuroleptic-induced tardive dyskinesias.
authors.affiliation: Psychiatric Research Centre, Uppsala, Sweden.
authors.forename: U
authors.initials: U
authors.lastname: Liminga
authors.forename: P
authors.initials: P
authors.lastname: Johansson
authors.forename: I
authors.initials: I
authors.lastname: Nylander
authors.forename: L M
authors.initials: LM
authors.lastname: Gunne
mesh_terms: D000374:Aggression / Q000187:drug effects*; D000818:Animals; D004409:Dyskinesia, Drug-Induced / Q000503:physiopathology*; D004745:Enkephalins / Q000008:administration & dosage / Q000494:pharmacology*; D005260:Female; D007263:Infusions, Parenteral; D008297:Male; D051381:Rats; D011919:Rats, Inbred Strains; D013378:Substantia Nigra / Q000187:drug effects*
chemical_list: D004745:Enkephalins