From the Departments of Anesthesiology (A.L.S., K.H., C.A.A., C.M.P., S.G., J.C.E.) Physiology and Pharmacology (R.C., H.S., J.C.E.) School of Medicine (B.P.), Wake Forest School of Medicine, Winston-Salem, North Carolina.
Anesthesiology. 2018 Sep;129(3):544-556. doi: 10.1097/ALN.0000000000002290.
WHAT THIS ARTICLE TELLS US THAT IS NEW: BACKGROUND:: Recovery from pain after surgery is faster after cesarean delivery than after other abdominal procedures. The authors hypothesized that recovery in rats after surgery could be reversed by antagonism of spinal oxytocin or vasopressin receptors, that there may be a sex difference, and that spinal oxytocin innervation could change after surgery.
Male and female rats underwent partial spinal nerve ligation surgery. Effects of nonselective and selective oxytocin and vasopressin 1A receptor antagonists on mechanical hypersensitivity during partial recovery were assessed (n = 8 to 14/group). Oxytocin immunoreactivity in the dorsal horn of the spinal cord (n = 7 to 8/group) and messenger RNA (mRNA) expression for oxytocin-binding receptors in dorsal root ganglia and spinal cord (n = 8/group) were measured.
Intrathecal injection of oxytocin and vasopressin receptor antagonists were similarly effective at reducing withdrawal threshold (in all experiments from 22 [19, 26] median [first quartile, third quartile]) g to 8.3 [6.4, 12] g after injection) in both sexes, while having no or minimal effects in animals without surgery. Oxytocin fiber immunoreactivity was 3- to 5-fold greater in lumbar than other regions of the spinal cord and was increased more than 2-fold in lumbar cord ipsilateral to surgery. Injury was also associated with a 6.5-fold increase in oxytocin receptor and a 2-fold increase in vasopressin 1A receptor messenger RNA expression in the L4 dorsal root ganglion ipsilateral to surgery.
These findings suggest that the capacity for oxytocin signaling in the spinal cord increases after surgery and that spinal oxytocin signaling plays ongoing roles in both sexes in recovery from mechanical hypersensitivity after surgery with known nerve injury.
本文的新意：背景：与其他腹部手术相比，剖宫产术后疼痛恢复更快。作者假设，手术后大鼠的恢复可以通过拮抗脊髓催产素或加压素受体来逆转，可能存在性别差异，并且手术后脊髓催产素神经支配可能会发生变化。
雄性和雌性大鼠接受部分脊髓神经结扎手术。评估非选择性和选择性催产素和加压素 1A 受体拮抗剂对部分恢复期间机械性超敏反应的影响（n = 8 至 14/组）。测量脊髓背角催产素免疫反应（n = 7 至 8/组）和背根神经节和脊髓中催产素结合受体的信使 RNA（mRNA）表达（n = 8/组）。
鞘内注射催产素和加压素受体拮抗剂在两性中同样有效地降低（在所有实验中从 22 [19,26]中位数[第一四分位数，第三四分位数]至 8.3 [6.4,12] g ）注射后）的撤回避疫阈值，而在未接受手术的动物中则没有或几乎没有作用。与其他脊髓区域相比，催产素纤维免疫反应在腰椎中高 3-5 倍，并且在与手术同侧的腰椎中增加了 2 倍以上。损伤还与手术后与手术同侧 L4 背根神经节中的催产素受体增加 6.5 倍和加压素 1A 受体 mRNA 表达增加 2 倍相关。
这些发现表明，手术后脊髓中催产素信号的能力增加，并且脊髓催产素信号在具有已知神经损伤的手术后机械性超敏反应恢复中在两性中都发挥着持续作用。
