Acetylcholinesterase (AChE)-positive innervation of the guinea-pig spleen.

The presence and intraorgan distribution of the acetylcholinesterase (AChE)-positive nerve structures in the guinea-pig spleen were studied by means of the direct thiocholine method. Visualized AChE-positive nerve fibres entered the guinea-pig spleen at its hilum in the vicinity of the splenic artery branches and intra parenchyma were gradually distributed to form thicker periarterial nerves and also fine adventitial nerve plexus. In described topography the AChE-positive nerve fibres were identified in association with the central artery running through the white pulp. Some of the perivascular nerve fibres associated with the central artery extended away and passed into the periarterial lymphatic sheath (PALS) to reach the marginal zone and in continuation entered into the mantle zone of lymphatic follicles. Several AChE-positive nerve fibres were seen in the red pulp but less in the splenic capsule. We did not find any AChE-positive nerve cells in the guinea-pig spleen.