MAO-A and MAO-B in the superior cervical ganglion and in the nictitating membrane of the cat

1. 1. The two forms of MAO, A and B, are present in the nictitating membrane and superior cervical ganglion of the cat. 2. 2. The K M for the substrate tyramine differed between both tissues, the affinity of the ganglionar enzyme was almost three times lower than that of the nictitating membrane. 3. 3. The potency of clorgyline to inhibit the form A of MAO, using tyramine as substrate, was lower in ganglia than in the nictitating membrane. 4. 4. Sympathetic denervation decreased type A to a greater extent than type B in the nictitating membrane. 5. 5. In superior cervical ganglion, clorgyline was a more potent inhibitor of noradrenaline metabolism than in the nictitating membrane.