title: Effects of urinary bladder distension on activity of T3-T4 spinal neurons receiving cardiac and somatic noxious inputs in rats.
abstract: The aims of this study were to examine effects of urinary bladder distension (UBD) on T(3)-T(4) spinal neurons receiving cardiac and somatic noxious inputs and to determine the pathway involved in transmitting urinary bladder inputs to thoracic spinal segments. Extracellular potentials of single T(3)-T(4) neurons were recorded in pentobarbital anesthetized male rats. Either bradykinin solution (10(-5) M) or an allogenic mixture (adenosine 10(-3) M, bradykinin, histamine, serotonin, prostaglandin E2 10(-5) M each) was administered intrapericardially. UBD was produced by saline inflation (0.5-2.0 ml, 20 s). Of 487 neurons tested for responses to UBD, 70 were inhibited and 37 were excited. Seventy-six out of 336 neurons received convergent input from UBD and heart; 69/76 viscerovisceral convergent neurons had somatic fields. Spinal transection at rostral C(1) abolished UBD inhibition in 5/9 neurons; whereas transections at L(1)-L(2) abolished UBD inhibition in 3/3 cells tested. Results showed that T(3)-T(4) spinal neurons processing cardiac and somatic nociceptive information were primarily inhibited by input from the urinary bladder through either supraspinal structures or direct intraspinal pathways.
authors.affiliation: Department of Physiology, University of Oklahoma Health Sciences Center, P.O. Box 26901, Oklahoma City, OK 73190, USA. chao-qin@ouhsc.edu
authors.forename: Chao
authors.initials: C
authors.lastname: Qin
authors.forename: Margaret J
authors.initials: MJ
authors.lastname: Chandler
authors.forename: Robert D
authors.initials: RD
authors.lastname: Foreman
mesh_terms: D000200:Action Potentials / Q000187:drug effects / Q000502:physiology; D000241:Adenosine / Q000008:administration & dosage; D000344:Afferent Pathways / Q000502:physiology*; D000818:Animals; D001920:Bradykinin / Q000008:administration & dosage; D015232:Dinoprostone / Q000008:administration & dosage; D004338:Drug Combinations; D004594:Electrophysiology / Q000379:methods; D006632:Histamine / Q000008:administration & dosage; D008297:Male; D009433:Neural Inhibition / Q000502:physiology; D009475:Neurons, Afferent / Q000502:physiology*; D010120:Oxytocics / Q000008:administration & dosage; D010812:Physical Stimulation; D011312:Pressure; D051381:Rats; D017207:Rats, Sprague-Dawley; D012701:Serotonin / Q000008:administration & dosage; D013116:Spinal Cord / Q000033:anatomy & histology / Q000502:physiology*; D013119:Spinal Cord Injuries / Q000503:physiopathology; D013268:Stimulation, Chemical; D001743:Urinary Bladder / Q000502:physiology*; D014553:Urinary Tract Physiological Phenomena
chemical_list: D004338:Drug Combinations; D010120:Oxytocics; D012701:Serotonin; D006632:Histamine; D000241:Adenosine; D015232:Dinoprostone; D001920:Bradykinin