NEURAL transmission in sympathetic ganglia has been regarded as an automatic relay involving only pre- and postganglionic neurones. It is now agreed, however, that the small, intensely fluorescent cells — at least some of which are interneurones1,2 — modulate transmission in the superior cervical ganglion. Greengard et al.3–6 have documented the role of the ganglionic interneurone in modulating ganglionic transmission. Dopamine released from an interneurone binds to a receptor on the surface of the ganglionic neurone, activating an adenylate cyclase. The increased production of cyclic AMP leads to hyperpolarisation of the ganglionic neurone by a mechanism which is still obscure.
About this article