Fig. 1. Innervation pattern of the vasoconstrictor muscle viewed by immunohistochemistry. (Ai) AMRP-immunoreactivity in the vicinity of the abdominal ganglion and three major arteries. The preparation is placed ventral side up except for the abdominal ganglion (the ganglion is rotated 180° to see the dorsal surface). The abdominal aorta is mainly innervated by the branches of the pericardial and spermathecal nerves (see Aii). Scale bar is 2 mm. Inset shows a higher magnification of a part of the abdominal aorta including the vasoconstrictor muscle. Note the extensive ramification of the immunopositive fibers. Scale bar in the inset is 1 mm. (Aii) Diagram of the preparation shown in Ai. AA, anterior aorta; AbA, abdominal aorta; AbG, abdominal ganglion; GA, gastroesophageal artery; Pn, pericardial nerve; Spn, spermathecal nerve; Vm, a region containing the vasoconstrictor muscle. (B) Immunopositive fibers and varicosities in the vasoconstrictor muscle. Scale bars in all figures are 100 µm. (Bi) AMRP-immunoreactivity. (Bii) Enterin-immunoreactivity. (Biii) NdWFamide-immunoreactivity.