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RESEARCH PRODUCT

Chapter 8 Nicotinic receptors of the vertebrate CNS: introductory remarks

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Publisher Summary This chapter focuses on the nicotinic receptors of the vertebrate central nervous system (CNS). In vertebrates, nicotinic cholinergic neurotransmission is found in both the CNS and the periphery (muscle endplate). Although muscle and neuronal nicotinic acetylcholine receptors (nAChR) have evolved from a common ancestor, it is striking that the muscle receptor has remained rather stable in evolution, whereas the neuronal receptor has evolved to a wide diversity of subtypes. As an attractive hypothesis, neurotransmitters and neurohormones may not only interact with their archetypic cognate receptors but also with other neuroreceptor, albeit in a modulatory fashion. By modulating the sensitivity and response kinetics of neuroreceptor to their natural transmitters, the action of allosteric regulators could not only provide additional levels of integration of response, or coincidence detection, but distinct local combinations and concentrations of chemical messengers could also produce messages of a new quality. By their implementation on sets of different receptors in neighboring synapses and spines, and by linking many of these locally distinct incidences on the cellular network level, the kind of neuronal activity may be produced that could be associated with higher order brain activity such as consciousness and mind. The chapter concludes that endogenous nicotinic non-competitive agonists (NCAs) are members of a much larger family of intracellular messengers, which are involved in higher order modes of control of CNS function.