TENSION-RESPONSE RELATIONSHIPS IN THE INTACT NICTITATING MEMBRANE OF THE PITHED CAT

¹ Department of Pharmacology, West Virginia University Medical Center, Morgantown, West Virginia

Increases in the resting tension, within the range of 0 to 12 g applied to the nictitating membrane, result in increases in the response to a constant dose of norepinephrine. Further increases in tension, up to 19 g, do not cause any further consistent changes in response. Dose-response curves determined under 1 to 2 g of resting tension, result in an apparent sensitivity which is only 1/10 of that determined under 10 to 12 g of resting tension. Denervation and decentralization, procedures which produce changes in the sensitivity of the nictitating membrane, cause little, if any, change in the relationship of response to resting tension.