Angiotensin II receptors in the lumbar spinal cord of the rat

Locations of cells responsive to microiontophoretically applied angiotensin II (AII) were compared distributions of AII receptor binding sites identified by autoradiography in the lumbar enlargement region of the rat spinal cord. Angiotensin II receptor binding sites were densely concentrated in the superficial layers of the dorsal horn. Considerably lower densities of binding sites were present in the remaining gray matter. Effects of microiontophoretically applied AII on lumbar spinal cord cells did not vary with location within the gray matter. AII facilitated firing of most cells in the lumbar whether the cells were in superficial or deeper laminae of the dorsal horn or in the ventral horn. The distribution of AII binding sites and the distribution of cells that were responsive to AII suggest that AII may play a role in modulating both sensory and motor functions of the spinal cord.