Monosynaptic Glutamatergic Activation of Locus Coeruleus and Other Lower Brainstem Noradrenergic Neurons by the C1 Cells in Mice

Holloway, B. B., Stornetta, R. L., Bochorishvili, G., Erisir, A., Viar, K. E., & Guyenet, P. G. (2013). "Monosynaptic Glutamatergic Activation of Locus Coeruleus and Other Lower Brainstem Noradrenergic Neurons by the C1 Cells in Mice." The Journal of Neuroscience, 33(48), 18792-18805. C1 and A1 neuronal cells are within the RVLM which is previously known to be activated by change in stresses and blood pressure. This study utilizes channelrhodopsin-2 (ChR2) and observes the expression of that gene in the brains of adult dopamine-β-hydroxylase (DβH) mice. This can observe the effects of C1 neurons on noradrenergic system. The study showed that ChR2 catecholaminergic cells were VGluT2 and had an excitatory affect on brainstem noradrenergic neurons. C1 and A1 cells did not express GABAergic or glycinergic markers (Comer et al., 1999; Schreihofer et al., 1999; Stornetta and Guyenet, 1999; Stornetta et al., 2002a). This experiment particularly observed the activity of the Locus Coeruleus (LC) neurons based on activation from the C1 neurons. C1 cells relay stimuli to sympathetic preganglionic neurons, LC, A1 and A2 noradrenergic neurons. Basically, the C1 cells are able to excite noradrenergic responses in the CNS. This helped me understand the process of the cascade of mice with dopamine-β-hydroxylase (DβH) which turns dopamine into norepinephrine. This study particularly observed specific C1, LC, and noradrenergic neurons activity. -CW