Adrenaline and Noradrenaline: Introduction

S Clare Stanford, University College London, London, UK

Published online: January 2006

DOI: 10.1038/npg.els.0004097

Adrenaline and noradrenaline are found in the adrenal gland and in neurons of the peripheral (autonomic) and central nervous systems. Synthesis of these catecholamines is tightly regulated and ensures that their supply is coupled to the rate of their release. Both adrenaline and noradrenaline help to maintain internal body state (‘homeostasis’) but, in the brain, they are thought also to influence arousal and mood.

Keywords: dopamine--hydroxylase; adrenaline; noradrenaline; sympathetic nervous system; locus coeruleus

Figure 1. The chemical structure of (a) noradrenaline (norepinephrine) and (b) adrenaline (epinephrine).
Figure 2. The synthetic pathway for noradrenaline (NA) and adrenaline in neuron terminals and chromaffin cells. Tyrosine, derived from the diet, is taken up into catecholamine-secreting neurons, where it is converted into DOPA in the neuronal cytoplasm. After conversion of DOPA into dopamine, the latter is taken up into the storage vesicles, where it is converted into NA by the enzyme DH. NA that leaks out of the vesicles is converted into adrenaline in the cytoplasm of neurons that contain PNMT. Vesicle stores of NA and adrenaline are maintained by active uptake via a protein transporter in the vesicle membrane.
Figure 3. The brainstem nuclei for neurons releasing noradrenaline or adrenaline. The main projections from the locus coeruleus are the (noradrenergic) dorsal bundle, the dorsal longitudinal fasciculus and the central tegmental tract. Some fibres of the dorsal bundle innervate the thalamus directly, whereas others, together with the central tegmental tract, join the medial forebrain bundle at the level of the caudal hypothalamus. This pathway then projects to many brain areas, including the amygdala nuclei, anterior thalamus, septum, olfactory areas and the neocortex. Fibres from the dorsal longitudinal fasciculus innervate the paraventricular nucleus and, possibly, the supraoptic nucleus in the hypothalamus. The medullary bundle, in which neurons from the locus coeruleus branch from the central tegmental tract, projects to the caudal medulla (not illustrated). Fibres from the central tegmental tract also descend to the spinal cord.
Figure 4. The distribution of neuronal projections from the locus coeruleus and lateral tegmental (noradrenaline) systems in the brain.
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 Further Reading
    book Brading A (1999) The Autonomic Nervous System and its Effectors. Oxford: Blackwell Science.
    book Fillenz M (1990) Noradrenergic Neurons. Cambridge, UK: Cambridge University Press.
    Foote SL, Bloom FE and Aston-Jones G (1982) Nucleus locus coeruleus: new evidence of anatomical and physiological specificity. Physiological Reviews 63: 844–913.
    Kalia M, Fuxe K and Goldstein M (1985) Rat medulla oblongata. II. Dopaminergic, noradrenergic (A1 and A2) and adrenergic neurons, nerve fibres and presumptive terminal processes. Journal of Comparative Neurology 233: 308–332.
    book Stanford SC (2001) "Noradrenaline". In: Webster RA (ed.) Neurotransmitters, Drugs and Brain Function, pp. 163–185. Chichester: Wiley.
    book Stanford SC and Salmon P (1993) Stress: From Synapse to Syndrome. London: Academic Press.

Related Sub-Topics:

Neurotransmitters | Receptors for Neurotransmitters | Information Flow | Other Biomolecules: Structure, Function, Metabolism
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Article Title: Adrenaline and Noradrenaline: Introduction
 
How to Cite close
Stanford, S Clare(Jan 2006) Adrenaline and Noradrenaline: Introduction. In: eLS. John Wiley & Sons Ltd, Chichester. http://www.els.net [doi: 10.1038/npg.els.0004097]