Fig. 4.

NTPDase2, NTPDase3, and ecto-5′-nucleotidase (E5′Nt) immunoreactivity (ir) in cultures of dissociated rat carotid body (CB). A–F: immunofluorescence staining of permeabilized cultures showing NTPDase2- and NTPDase3-ir (green; A and D, respectively) associated within a TH-ir (red; B and E) type I cell cluster; merged images are shown in C and F (n = 4). G–I: similarly, E5′Nt-ir (green; G) is associated with a TH-ir type I cluster (red; H); merged image is shown in I (n = 3). J–L: demonstration of E5′Nt-ir in an isolated glial fibrillary acidic protein (GFAP)-positive type II cell (n = 2). M–O and S–U: nonpermeabilized CB cultures showing a type I cell cluster (arrow in phase contrast image, M and S), expressing positive, extracellular NTPDase2 and NTPDase3 immunoreactivity (N and T), respectively, and merged images in O and U; note NTPDase2- and -3 negative background cells surrounding the type I cell cluster in N and T (n = 3). P–R: isolated spindle-shaped, putative glial-like type II cell (arrow) in a CB culture is selectively immunopositive for NTPDase2 (green; Q); note NTPDase 2-negative background cells in Q (n = 2).