Age dependence of motor activity and sensitivity to dopamine receptor 1 agonist, SKF82958, of inbred AKR/J, BALB/c, C57BL/6J, SAMR1, and SAMP6 strains

• Published in: Brain research 2009-01, Vol.1250, p.175-182
• Main Authors: Niimi, Kimie, Takahashi, Eiki, Itakura, Chitoshi
• Format: Article
• Language: English
• Subjects: Aging; Aging - physiology; Analysis of Variance; Animals; Benzazepines - pharmacology; Biological and medical sciences; Development. Senescence. Regeneration. Transplantation; Dopamine Agonists - pharmacology; Dopamine receptor 1; Fundamental and applied biological sciences. Psychology; Male; Mice; Mice, Inbred AKR; Mice, Inbred BALB C; Mice, Inbred C57BL; Mice, Inbred Strains; Motor activity; Motor Activity - physiology; Neurology; Receptors, Dopamine D1 - agonists; SAMP6; SKF82958; Vertebrates: nervous system and sense organs
• ISSN: 0006-8993; 1872-6240
• DOI: 10.1016/j.brainres.2008.10.043

Abstract Motor activity is a key component in many behavioral tests. To assess the relationship between aging and activity, we recorded motor activity for 72 consecutive hours for C57BL/6J (B6J), BALB/c, AKR/J, senescence-accelerated mouse prone 6 (SAMP6), and senescence-accelerated mouse resistant 1 (SAMR1) strains at the ages of 6 and 12 months. Further, to examine whether the dopamine receptor 1 (D1) signaling system is associated with the age-related alteration of activity, we evaluated the motor activity of the mice treated with SKF82958 (6-chloro-7,8-dihydroxy-3-allyl-1-phenyl-2,3,4,5-tetrahydro-1-phenyl-1H-3-benzazepine hydrobromide), a D1 agonist. Twelve-month-old B6J showed higher activity on day 1 and higher D1 sensitivity than 6-month-old mice. Twelve-month-old BALB/c showed higher activity on day 3 and a slightly lower threshold of D1 than 6-month-old mice. Twelve-month-old AKR/J, SAMR1 and SAMP6 strains showed lower motor activity than 6-month-old mice. The D1 sensitivities in 12-month-old AKR/J and SAMR1 were similar to those of corresponding 6-month-old mice, whereas the D1 sensitivity of 12-month-old SAMP6 was significantly lower than that of 6-month-old SAMP6. SKF82958 significantly increased the motor activity of 6-month-old SAMP6 compared with age-matched, AKR/J and SAMR1. Our results indicate that D1 contributes substantially to the age-related increase of activity in B6J, but not to that in BALB/c. In AKR/J, SAMR1, and SAMP6, an age-related decrease of activity was observed. The contribution of D1 to this appeared to be small in AKR/J and SAMR1, but substantial in SAMP6. Thus, the contribution of D1 to age-related changes of motor activity is strongly strain-dependent.