Gene products from LUQ neurons in the abdominal ganglion are present at the renal pore of Aplysia californica

The L2-4,6 and L5 cells located in the left upper quadrant of the abdominal ganglion of Aplysia californica express the L5-67 and LUQ-1 genes, respect ively, in a nonoverlapping manner. These cells send major neurites to the k idney and at least some of them were shown to innervate the renal pore clos er muscle, and thereby control its function. By using in-situ hybridization and immunofluorescence, the presence of L5-67 and LUQ-1 mRNAs and peptides was studied in the kidney, with emphasis on the region of the renal pore. We detected immunoreactive materials in many small varicose nerve fibers ru nning along the central epithelium in the inner parts of the kidney, and in neurites located within a large nerve associated with muscles inside the r enal pore. Our observations represent the first direct evidence of the pres ence of gene products from LUQ cells at the renal pore, suggesting that the y may be responsible for mediating LUQ cell signals. Furthermore, mRNAs cod ing for the L5-67 and LUQ-1 peptides were also found in the nerve structure inside the renal pole. Our report documents a striking example of neuropep tide mRNA targeting nerve terminals that are very distant from their cell b odies. (C) 2000 Elsevier Science Inc. All rights reserved.