Failure of urethane anesthetic to block induction of pineal serotonin N-acetyltransferase activity in the rat.

Ability of urethane anesthetic to block induction of pineal serotonin N-acetyltransferase (SNAT; E.C.2.3.1.5) activity was measured in individual rat pineal glands in animals receiving urethane (25% w/v, IP, 1.2 g/kg) or saline, 6 hr prior to sacrifice. Using a radioenzymatic assay, SNAT determinations were made twice daily (at 1200 or 2400 hr) immediately after the sacrifice of each animal. The results show that urethane had no effect on the induction of SNAT activity: (1) implying that the neural activity of those structures involved in induction of SNAT activity (e.g., suprachiasmatic nucleus) is not substantially altered by this anesthetic and (2) suggesting that the central blockade of ovulation by urethane does not include alterations in suprachiasmatic nucleus activity.