Dale s Principle

With the multitude of different types of transmitters, the question arises whether a single neuron can release more than one transmitter. Dale s principle stated that... 

The neurotransmitter phenotype, (i.e., what type of neurotransmitter is stored and ultimately will be released from the synaptic bouton) is determined by the identity of the neurotransmitter transporter that resides on the synaptic vesicle membrane. Although some exceptions to the rule may exist all synaptic vesicles of a given neuron normally will express only one transporter type and thus will have a dehned neurotransmitter phenotype (this concept is enveloped in what is known as Dale s principle see also Reference 19). To date, four major vesicular transporter systems have been characterized that support synaptic vesicle uptake of glutamate (VGLUT 1-3), GABA and glycine (VGAT), acetylcholine (VAChT), and monoamines such as dopamine, norepinephrine, and serotonin (VMAT 1 and 2). Vesicles that store and release neuropeptides do not have specific transporters to load and concentrate the peptides but, instead, are formed with the peptides already contained within. 

The metabolic unity of the neuron requires that the same transmitter is released at all its synapses. This is known as Dale s Law (or principle) which Sir Henry Dale proposed in 1935. Dale s Law only applies to the presynaptic portion of the neuron, not the postsynaptic effects which the transmitter may have on other target neurons. For example, acetylcholine released at motor neuron terminals has an excitatory action at the motor neuron junction, whereas the same transmitter released at vagal nerve terminals has an inhibitory action on the heart. 

Pratt WB, Taylor P. Principles of drug ac-tion-the basis of pharmacology. S ed. New York Churchill Livingstone 1990. Rang HP, Dale MM, Ritter JM, Gardiner P. Pharmacology. 4 ed. New York Churchill Livingstone 1999. 

CONTENTS 1. Basic Principles (J. W. Robinson). 2. Instrumental Requirements and Optimisation (J. E. Cantle). 3. Practical Techniques (J. E. Cantle). 4a. Water and Effluents (B. J. Farey and L A. Nelson). 4b. Marine Analysis by AAS (H. Haraguchi and K. Fuwa). 4c. Analysis of Airborne Particles in the Workplace and Ambient Atmospheres (T.J. Kneip and M. T. Kleinman). 4d. Application of AAS to the Analysis of Foodstuffs (M. Ihnat). 4e. Applications of AAS in Ferrous Metallurgy (K. Ohis and D. Sommer). 4f. The Analysis of Non-ferrous Metals by AAS (F.J. Bano). 4g. Atomic Absorption Methods in Applied Geochemistry (M. Thompson and S. J. Wood). 4h. Applications of AAS in the Petroleum Industry W. C. Campbell). 4i. Methods forthe Analysis of Glasses and Ceramics by Atomic Spectroscopy (W. M. Wise et al.). 4j. Clinical Applications of Flame Techniques (B.E. Walker). 4k. Elemental Analysis of Body Fluids and Tissues by Electrothermal Atomisation and AAS (H. T. Delves). 4I. Forensic Science (U. Dale). 4m. Fine, Industrial and Other Chemicals. Subject Index. (All chapters begin with an Introduction and end with References.)... 

Loewi s discovery led to a chain reaction which resulted in the rapid spread of the principle of chemical transmission to all the peripheral synapses in the autonomic nervous system, and to the discovery of chemical transmission from the somatic motor nerve to the skeletal muscles and from one neuron to another, first in the autonomic and then in the central nervous system (studies of Samoilov, the classical experiments of the Dale and Cannon groups, the investigations of Ecdes, and many others). Finally, the chemical theory was confirmed by modem experiments using the latest methods electron microscopy, histochemical methods, the microelectrode technique, and others ... 

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