Figure 4.

TAARs are expressed in neonatal rat spinal cord. (A) RT-PCR evidence of TAAR expression in both sexes. In males, TAARs 2,5, and 6 expression was weakest, and in females, TAARs 2,6, and 9 were weakest. (B) RT-PCR series directly comparing TAAR1 and TAAR4 expression in both sexes as these receptors are known to be activated by trace amines. (C) TAAR1 mRNA expression in spinal neurons. In situ hybridization reveals TAAR1 labeling throughout the P2 rat spinal cord ventral horn (compare sense to antisense). Highlighted regions in sense panel approximately identify same central canal and motor nucleus location in antisense panels. (D) TAAR1 receptor immunolabeling is found in many spinal neurons, including those associated with the central canal (asterisks; left), and in the ventral horn, including putative motoneurons (right). Note thread-like projections adjacent to epithelial cells with expansion in central canal interior. (E) TAAR4 receptor immunolabeling is also found in many spinal neurons and appears to localize in cells ventral to the central canal (left) and in the gray matter ventral horn, including putative motoneurons (right). All images are grayscale negatives. Scale bars: (C), 100 μm; (D,E), 25 μm. Confocal images in (D,E) were taken at 0.30 μm optical section thickness.