Neurohumoral control of blood vessels: some future directions

The recent discoveries of vascular neuroeffector control mechanisms, involving a wide variety of neurohumoral agents, pre- and postjunctional neuromodulation, and cotransmission, leave the field poised for growth in new directions. Some of these are outlined in this article, including: the development of methods for quantitation of the pattern and density of different types of perivascular nerves; exploration of the potent actions of purine nucleotides and nucleosides on vascular smooth muscle and/or endothelial cells, particularly in relation to the development of drugs of therapeutic potential; expansion of studies of the regulatory implications of cotransmitter release of ATP together with noradrenaline from some sympathetic perivascular nerves and of VIP together with acetylcholine from some parasympathetic nerves; autoradiographic localization of receptors for monoamines, peptides of and purines in blood vessels; wider studies of "axon reflex" control of the circulation and of the roles of substance P; investigation of development, aging, and regeneration of different perivascular nerve types, and the long-term "trophic" actions of some neurohumoral agents. Lastly, the time is ripe to study abnormalities in neurohumoral control of vessels in disease and after chronic exposure to drugs.