Autoradiographic distribution of μ, δ and κ opioid binding sites in the superficial dorsal horn, over the rostrocaudal axis of the rat spinal cord

Abstract

Listen

Translate article

The purpose of this study was to use [ 3H]DAMGO, [ 3H]DTLET and [ 3H]EKC in the presence of 100 nM DAMGO and 100 nM DTLET, combined with a quantitative autoradiography to analyse the different proportions and the rostrocaudal distribution of μ, δ and κ opioid binding sites in the superficial layers (laminae I and II) of the cervical (C 6–C 8), thoracic (T 5–T 7), lumbar (L 3–L 5) and sacral (S 2–S 3) dorsal horn of the rat. The proportions of the three main types of opioid binding sites, assessed by autoradiography in laminae I and II, were found homogeneous at each segmental level considered: 70.4–74.3%, 18.4–20.3% and 7.3–9.5% for μ, δ, κ sites, respectively. The physiological relevance of these data is discussed.