Department of Biology, University of Utah, Salt Lake City, UT 84112, USA.
Proc Natl Acad Sci U S A. 2012 Jan 31;109(5):1388-95. doi: 10.1073/pnas.1118833109. Epub 2012 Jan 23.
We describe a functional profiling strategy to identify and characterize subtypes of neurons present in a peripheral ganglion, which should be extendable to neurons in the CNS. In this study, dissociated dorsal-root ganglion neurons from mice were exposed to various pharmacological agents (challenge compounds), while at the same time the individual responses of >100 neurons were simultaneously monitored by calcium imaging. Each challenge compound elicited responses in only a subset of dorsal-root ganglion neurons. Two general types of challenge compounds were used: agonists of receptors (ionotropic and metabotropic) that alter cytoplasmic calcium concentration (receptor-agonist challenges) and compounds that affect voltage-gated ion channels (membrane-potential challenges). Notably, among the latter are K-channel antagonists, which elicited unexpectedly diverse types of calcium responses in different cells (i.e., phenotypes). We used various challenge compounds to identify several putative neuronal subtypes on the basis of their shared and/or divergent functional, phenotypic profiles. Our results indicate that multiple receptor-agonist and membrane-potential challenges may be applied to a neuronal population to identify, characterize, and discriminate among neuronal subtypes. This experimental approach can uncover constellations of plasma membrane macromolecules that are functionally coupled to confer a specific phenotypic profile on each neuronal subtype. This experimental platform has the potential to bridge a gap between systems and molecular neuroscience with a cellular-focused neuropharmacology, ultimately leading to the identification and functional characterization of all neuronal subtypes at a given locus in the nervous system.
我们描述了一种功能分析策略，用于鉴定和描述外周神经节中存在的神经元亚型，并将其推广到中枢神经系统中的神经元。在这项研究中，从小鼠分离的背根神经节神经元暴露于各种药理学试剂（挑战化合物），同时通过钙成像同时监测>100 个神经元的个体反应。每种挑战化合物仅在背根神经节神经元的一部分中引起反应。使用了两种一般类型的挑战化合物：改变细胞质钙浓度的受体（离子型和代谢型）激动剂（受体激动剂挑战）和影响电压门控离子通道的化合物（膜电位挑战）。值得注意的是，后者包括 K 通道拮抗剂，它们在不同细胞中引起出乎意料的不同类型的钙反应（即表型）。我们使用各种挑战化合物根据其共享和/或不同的功能、表型特征来鉴定几种假定的神经元亚型。我们的结果表明，多种受体激动剂和膜电位挑战可以应用于神经元群体，以鉴定、表征和区分神经元亚型。这种实验方法可以揭示与赋予每个神经元亚型特定表型特征的质膜大分子的组合。该实验平台具有在以细胞为中心的神经药理学与系统和分子神经科学之间架起桥梁的潜力，最终导致在神经系统的给定位置鉴定和功能表征所有神经元亚型。
