QUALITATIVE COMPARISON BETWEEN THE PHARMACOLOGICAL PROPERTIES OF NICTITATING MEMBRANE-SUPERIOR CERVICAL GANGLION PREPARATIONS OF RABBIT AND CAT

1. The responses of the nictitating membrane and superior cervical ganglion of rabbit and cat to drugs were studied qualitatively in vivo. 2. Responses of the rabbit preparation to drugs affecting adrenergic and cholinergic neurohumoral transmission were similar to those of the cat. 3. Continuous preganglionic stimulation with supramaximal pulses at a half-maximal repetition rate facilitated the detection of drug-induced changes in peripheral and ganglionic sympathetic transmission. 4. Responses of the rabbit preparation to drugs affecting histamine and tryptaminic receptors were similar to those of the cat, with two exceptions, namely: (i) Effects supposingly mediated via H2-receptors in the superior cervical ganglion of cats, were not observed with rabbits; (ii) Effects of morphine presumably due to inhibition of transmitter-release from postganglionic nerve endings were observed in cats but not in rabbits. 5. As a pharmacological model the nictitating membrane/superior cervical ganglion preparation of rabbits was found to be equivalent to that of cats. © 1979.