Laminar compartmentalization of GABAA-receptor subtypes in the spinal cord: an immunohistochemical study

摘要: To assess the significance of GABAA-receptor heterogeneity, which is based on a family at least 15 subunits, cellular localization and subunit composition subtypes were analyzed immunohistochemically in rat spinal cord. The distribution subunits alpha 1, 2, 3, 5, beta 2,3, gamma 2 was investigated with subunit-specific antibodies, their colocalization within individual neurons visualized by double-immunofluorescence staining. results reveal widespread expression cord, whereas three other displayed more restricted, lamina-specific distribution. 1 5 most abundant intermediate zone, predominant superficial layers dorsal horn somatic preganglionic motoneurons. From studies, seven combinations could be identified (alpha 3/beta 2,3/gamma 2; 2/beta 1/beta 5/beta 1/alpha 2/gamma 2/alpha 5/gamma 2) that correspond presumably to distinct receptor subtypes. Although expressed triplet x/beta 2,3 not detected motoneurons may thus possess “atypical” 2). ON subcellular level, aggregates immunoreactivity, suggestive postsynaptic GABAA receptors, typically seen surface neuronal somata proximal dendrites. In addition, an intense diffuse staining observed laminae I--III for localized primary afferent terminals. GABAA- laminar compartments cord suggests heterogeneity relevance modulation sensory inputs, nociception, motor control segmental levels.