%0 Journal Article
%T Genetic marking and characterization of Tac2-expressing neurons in the central and peripheral nervous system
%A Lynn Mar
%A Fu-Chia Yang
%A Qiufu Ma
%J Molecular Brain
%D 2012
%I BioMed Central
%R 10.1186/1756-6606-5-3
%X By crossing Tac2-Cre mice with ROSA26-tdTomato reporter mice, we directly visualized Tac2 lineage neurons in the dorsal root ganglia, the dorsal horn of the spinal cord, and many parts of the brain including the olfactory bulb, cerebral cortex, amygdala, hippocampus, habenula, hypothalamus, and cerebellum. This Tac2-Cre allele itself was a null allele for the Tac2 gene. Behavioral analyses showed that Tac2 homozygous null mice responded normally to a series of algogenic (pain-inducing) and pruritic (itch-inducing) stimuli.Tac2-Cre mice are a useful tool to mark specific subsets of neurons in the sensory ganglia, the dorsal spinal cord, and the brain. These mice can also be used for future genetic manipulations to study the functions of Tac2-expressing neurons or the functions of genes expressed in these neurons.The spinal cord dorsal horn has long been recognized as the processing center for sensory information including pain, itch, cold, and warmth [1-4]. The dorsal horn is divided into five laminae, which can be identified by lamina-specific innervation by primary sensory fibers and by the expression of molecular markers [3]. For example, neurons in superficial laminae that express the neurokinin 1 receptor (NK1R) and the gastrin-releasing peptide receptor (GRPR) are involved in sensing pain and/or itch [5-7]. Neurons in the inner layer of lamina II that express protein kinase C ¦Ã (PKC¦Ã) are the targets of myelinated non-nociceptive afferents [8], and mediate nerve injury-induced mechanical allodynia, a type of pain evoked by innocuous mechanical stimuli [9]. Despite significant progress, the neural circuits that process specific somatic sensory information in the dorsal horn are still not well characterized [3].Tachykinin peptides are encoded by the tachykinin 1 (Tac1) and tachykinin 2 (Tac2) genes and are known to modulate neuronal activity [10]. Tac1 encodes a precursor protein that produces two peptides, substance P (SP) and neurokinin A (NKA), whereas Tac2 en
%U http://www.molecularbrain.com/content/5/1/3