Figure 5.

Uroguanylin (UGN) Ca²⁺ signaling pathway in the cortical astrocytes of brain slices. mRNA of guanylate cyclase C (GC-C) (341 bp) is expressed in the hypothalamus (H), midbrain (MB), cerebral cortex (Cx), and cerebellum (Cb) but not in astrocytes (A) (A). M – marker, In – intestine as positive control, Neg – negative control, glyceraldehyde 3-phosphate dehydrogenase (GAPDH, 235 bp) was used as cDNA control. Ca²⁺ measurements were performed only in SR101-positive cells (B) of GC-C knockout (KO) (left, the number of animals is 3, the number of brain slices is 6, the number of cells is 32) and UGN KO (right, the number of animals is 3, the number of brain slices is 5, the number of cells is 14) cerebral cortex, and the results are compared with those of their wild-type littermates (GC-C WT: the number of animals is 4, the number of brain slices is 6, the number of cells is 28; UGN WT: the number of animals is 3, the number of brain slices is 5, the number of cells is 17). In neurons of the cerebral cortex of WT animals, UGN did not affect the intracellular Ca²⁺ concentration (the number of animals is 4, the number of brain slices is 8, the number of cells is 43). Hyperkalemia of 30 mM was used as a positive control (C). The results are shown as mean ± standard deviation (SD) ΔF/F₀ is change of light output in time (ΔF) over initial brightness (F₀). Bar represents 10 s.