EXTRANEURONAL UPTAKE AND METABOLISM IN RAT SALIVARY GLANDS

Publisher Summary This chapter discusses the extraneuronal uptake and metabolism in rat salivary glands. Most data on the basics of extraneuronal uptake and metabolism in glandular tissue have been obtained from in vitro -studies. Protriptyline, a tricyclic antidepressant known to effectively inhibit the neuronal amine uptake by the membrane pump mechanism exerts, when included in the incubation medium in a concentration of 1 μg/ml, generally the same effects on the retention of amine and metabolites as does denervation. It is found that when various concentrations of protriptyline is included in the incubation of normal salivary gland slices, there seems to occur a gradual shift with increasing concentrations of the drug from mainly neuronal retention of unchanged 3 H-NA to extraneuronal retention of 3 H-NM and to a lesser extent some other metabolites. At maximally effective concentrations of protriptyline the metabolic picture is the same as in denervated slices. The described metabolic picture in the in vitro situation is quite similar to that found in vivo with the exception that the uptake of 3 H-NA in the atrophied gland is severely reduced, probably because of a reduced blood flow in such glands.