Intrathecal dynorphin A1-13 and dynorphin A3-13 reduce rat spinal cord blood flow by non-opioid mechanisms.
Radiolabeled microspheres were used to examine the effects of paralytic intrathecal doses of dynorphin A (Dyn A1-13) and Dyn A3-13 on rat brain and spinal cord blood flows and cardiac output. Dyn A1-13 produced significant dose-related reductions in blood flow to lumbosacral and thoracic spinal cord without altering cardiac output and blood flow to brain and cervical spinal cord. Naloxone failed to block these effects. Dyn A3-13, which lacks opioid activity, also significantly reduced blood flow in lumbosacral spinal cord. Thus, the paralytic effects of Dyn A in the rat may involve reductions in spinal cord resulting from non-opioid actions of Dyn A.
D000818:Animals; D001921:Brain / Q000098:blood supply*; D002302:Cardiac Output / Q000187:drug effects*; D002560:Cerebrovascular Circulation / Q000187:drug effects; D004399:Dynorphins / Q000008:administration & dosage / Q000494:pharmacology*; D007278:Injections, Spinal; D008297:Male; D009270:Naloxone / Q000494:pharmacology; D010446:Peptide Fragments / Q000008:administration & dosage / Q000494:pharmacology*; D051381:Rats; D011919:Rats, Inbred Strains; D012039:Regional Blood Flow / Q000187:drug effects; D013116:Spinal Cord / Q000098:blood supply* / Q000187:drug effects
D010446:Peptide Fragments; D009270:Naloxone; C026843:dynorphin (1-13); D004399:Dynorphins; C045478:dynorphin (3-13)