PT  - JOURNAL ARTICLE
AU  - GEWIRTZ, GEORGE P.
AU  - KOPIN, IRWIN J.
TI  - EFFECT OF INTERMITTENT NERVE STIMULATION ON NOREPINEPHINE SYNTHESIS AND MOBILIZATION IN THE PERFUSED CAT SPLEEN
DP  - 1970 Nov 01
TA  - Journal of Pharmacology and Experimental Therapeutics
PG  - 514--520
VI  - 175
IP  - 2
4099  - http://jpet.aspetjournals.org/content/175/2/514.short
4100  - http://jpet.aspetjournals.org/content/175/2/514.full
SO  - J Pharmacol Exp Ther1970 Nov 01; 175
AB  - Norepinephrine-C14 is synthesized in the cat spleen perfused with tyrothne-C14 and is released during nerve stimulation. There is a more rapid increase in the specific activity of released norepinephrine-C14 from spleens stimulated every 2 minutes than in that released from spleens stimulated every 10 minutes. After 3000 impulses delivered at 30 impulses/sec at intervals of either 2 minutes or 10 minutes, the specific activity of the released norepinephrine-C14 is greater than that remaining in the spleen, indicating selective release of newly synthesized norepinephrine. The ratio of the specific activity of norepinephrine-C14 released to that remaining in the spleen is higher with more frequent stimulation. In the presence of phenoxybenzamine the rate of increase of the specific activity of released norepinephrine-C14 is more rapid than in its absence; there is selective release of newly synthesized norepinephrine, but the ratio of specific activity of released to splenic norepinephrine-C14 is lower, indicating more rapid equilibration of norepinephrine stores as well as more rapid synthesis of the catecholamine. After perfusion for four hours the specific activity of the released norepinephrine-C14 is about 0.7 of the specific activity of norepinephrine totally derived from the perfused tyrosine-C14. These results suggest that newly synthesized norepinephrine plays a significant role in maintaining transmitter release and that this role varies with the interval between stimulation. © 1970 by The Williams & Wilkins Co.