6-OHDA-Induced Changes in Colonic Segment Contractility in the Rat Model of Parkinson’s Disease

Figure 1

Tissue dissection and preparation and 6-OHDA-induced dopamine (DA) lesion. The distal colon, proximal colon, and distal ileum tissues were excised by first cutting three, each 4–5 cm long tissue pieces, from ≈3 cm from the anus, and 3 cm from each side of the aboral and oral end of the caecum, respectively (shaded sections in a). Segments were then prepared from these 4–5 cm long tissue pieces by further cutting ≈10–15 mm long tubes of each tissue type (scissor markings), followed by attaching a silk thread to each end closing the luminal space (b). In a subset of the ≈10–15 mm long tubes, inverted segments were created by turning the tissue inside out, exposing the luminal space but closing the mucosal space (c). The longitudinal and circular strips were also prepared from the 4 to 5 cm long tissue pieces. The longitudinal strip was prepared by cutting a ≈10–15 mm long segment, opening it up along the mesenteric line, splitting in half with a width of ≈5 mm, and attaching a thread at each end (d). The circular strips were prepared by cutting a ≈5 mm long segment, rotating it 90°, opening it up along the mesenteric line, and attaching a thread at each end (e). The saline injection (Sham) did not affect the DA fibers (f), whereas the 6-OHDA injections (6-OHDA) in the medial forebrain bundle induced an almost complete DA fiber degeneration in the striatum (g).