Neurochemical Transducer Systems

Abstract

The availability of highly labeled norepinephrine makes it possible to label directly norepinephrine at sympathetic nerve endings. The results using tritiated norepinephrine (and serotonin) show that norepinephrine is formed at a constant rate and that the steady-state level at nerve endings is a balance between continuous synthesis and loss. Using these labeled amines, their turnover and release can be studied in the intact animal where structural integrity, essential for function of nerve endings, is not destroyed. A provisional model of a neurochemical transducer has been formulated as an integrated biophysical unit containing all the apparatus for synthesis, storage, release and metabolism of the neurohormone. It is stressed that synthesis, storage, release and metabolism of a neurohormone are not unrelated phenomena and must be considered together in interpreting drug action. The action of a number of drugs is discussed in relation to the neurochemical trans -ducer. These concepts may aid understanding of the intrinsic mechanism of function of nerve endings. [45 references].