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ALTERATIONS OF G PROTEIN ALPHA SUBUNITS IN HEART AND AORTA OF OLD RAT

ZHOU YUAN-GUO, XIONG REN-PING , WANG ZHENG-GUO

Deyartnmt 4，The Research Institute of Surgery, The Third Military Medical University, Chongqing 630042)

Abstract

Alterations in responsiveness to stimulation of G protein-coupled receptors in the cardiovascular system have been noted during aging and may be due to changes in the G proteins. The levels of G protein a subunits (Gs a, Go a and Gi a) and their mRNAs(Gs a，Go a，Gi 2a and Gi 3a) were examined in the aorta，heart，and brain of 6 and 24 month old fischer 344 rats by Western blot analysis，quantitative RNA dot blot hybridization and Northern Blot analysis. There were four bands (52，45，42 and 38 kD)in the aorta for Gsa. The 42 kD band decreased significantly in 24 month old rats (69. 2士0.2%，PCO. 05)，while the other bands did not change. The Go a and the Gi a contain spectively only a band of 39 kD and of 41 kD which decreased signify cantly in the 24 month rats by 71. 8士10. 70o and 63. 1士10. 40o;There were no significant changes in the level of Ga mRNA between 6 and 24 month old rats. In the
heart anti-Gsa antiserum could detect 3 bands(52，4 5 and 4 2 kD) which did not
change during aging;the levels of Gi a and Go a also did not change，but the mRNAs for Gi 2a and Gi 3a were significantly increased respectively to 120. 8士8. 4%and 136. 4士14. 2%.The above results indicated that the decrease of levels of Gi a Goa expression may be the molecular basis for the alterations in signal transduction and biological response of aging aorta and heart.

Key words: G proteins;Aging;cardiovascular;Rats;signal transduction

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Citing This Article：

ZHOU YUAN-GUO, XIONG REN-PING , WANG ZHENG-GUO. ALTERATIONS OF G PROTEIN ALPHA SUBUNITS IN HEART AND AORTA OF OLD RAT. Acta Physiol Sin 1996; 48 (3): (in Chinese with English abstract).