The antidyskinetic action of dihomo‐γ‐linolenic acid in the rodent

Open Access
Publisher Website
Google Scholar
Abstract
The antidyskinetic action of dihomo‐γ‐linolenic acid (DHLA) was assessed against dyskinesias induced in the guinea‐pig by dopamine injected into the striatum (200 μg bilateral 2 h after nialamide, 75 mg kg−1, i.p.) and in the guinea‐pig and rat by 2‐di‐n‐propylamino‐5, 6‐dihydroxytetralin (tetraiin), 0.025 mg kg−1, s.c. Dopamine and tetralin‐induced dyskinesias in the guinea‐pig were reduced or abolished by DHLA given i.p., 30−100 mg kg−1, given once daily for 5–10 days. Tetralin‐induced dyskinesias were antagonized by DHLA given orally to the guinea‐pig (50−200 mg kg−1, 5 days) or in the diet to the rat (approximately 200 mg kg−1 daily for 10−14 days). DHLA injected into the striatum (2.5−20 μg bilateral, 2–4 days) also antagonized tetralin‐induced dyskinesias in the rat. The antidyskinetic action of DHLA given i.p. to the guinea‐pig could be antagonized by aspirin or eicosa‐5,8,11,14‐tetraynoic acid (100 mg kg−1 i.p. daily, starting 2 days before a 5 day treatment with DHLA). Aspirin (25−100 mg kg−1, i.p.) dose‐dependently antagonized the antidyskinetic activity of 5 and 20 μg DHLA given bilaterally into the striatum (2 days). DHLA (100 mg kg−1 i.p.) given daily for 10 days or approximately 200 mg kg−1 DHLA (daily for 10–14 days given in the diet) administration to the rat failed to modify the stereotyped behaviour induced by apomorphine, 0.5 or 2 mg kg−1 s.c., to induce catalepsy, or to modify the cataleptic effects of haloperidol 0.25 or 1 mg kg−1 i.p. It is suggested that the selective inhibition of dyskinesias in the rodent by DHLA may reflect a striatal effect with a dependency on conversion to prostaglandins.