Changes in outflow facility and content of norepinephrine in iris and ciliary processes of albino rabbits after cervical ganglionectomy.

Changes in outflow facility and in the content of norepinephrine in the iris and ciliary processes of the rabbit eye have been followed at early and late intervals after cervical ganglionectomy. Outflow facility was measured in vivo with a constant rate infusion technique. Norepinephrine tissue levels ivere determined by fluorescence spectrometry. The results indicate that the "early" increase in outflow facility after ganglionectomy is associated with a rapid decrease in the norepinephrine content of the iris and ciliary processes. The "late" decrease in outflow facility persists as long as the iris and ciliary processes are depleted of norepinephrine. A return to more normal levels of outflow facility occurs as norepinephrine levels begin to reappear in the tissues. The relationship between these later-than-24-hour changes in facility and the changes in tissue concentration of norepinephrine is discussed. Some support for this relationship was derived from experiments xoith bilateral ganglionectomy. Bilateral ganglionectomy prolongs the duration of the facility decrease and similarly induces a depletion of tissue norepinephrine of greater duration than that accompanying unilateral denervation.