CORRELATION BETWEEN ACTIVITIES OF NA-ATPASE AND ACETYLCHOLINESTERASE IN POSTNATALLY DEVELOPING RAT-BRAIN(,K+)

Na+,K+-ATPase, Mg2+ ATPase and acetylcholinesterase (AChE) activities were estimated in homogenised rat brain from the age of 2 days to 20 m onths. These activities were present in 2-day-old rats, indicating tha t the enzymes are mature soon after birth. Mg2+-ATPase activity remain ed constant in neonate, adult and senescent animals. AChE activity was increased about 120% in 8-day-old compared to 2-day-old animals Na+,K +-ATPase was stimulated about 30% from 2-day-old to 21-day-old rats. T hese enzymatic changes may indicate a proliferation of membranes and s ynaptogenesis during early postnatal development. AChE activity declin ed about 30% from day 8 to day 21, possibly reflecting the concurrent increase in Na+,K+-ATPase activity. Thereafter, this activity decrease d by approximately 18% up to 20 months postnatally. Na+,K+-ATPase acti vity was increased about 45% from day 21 to 20 months. This enzyme act ivity may be induced mainly by an age associated increase in glial cel ls activity.