Effects of H_2S on visceral pain induced by colorectal distention and expression of substance P in rats / 中华消化杂志

ABSTRACT

Objective To study the effects of H_2S on the visceral pain induced by colorectal dis- tention (CRD) and the expression of substance P (SP)in rats.Methods Forty Wistar rats were randomly divided into control group,normal saline(i,p.) group,low( 15?mol/kg),moderate (45?mol/kg) and high(75?mol/kg) dose of NaSH(i.p.) groups.All rats.except control group,were subjected to CRD for 25 seconds and their behavioral responses to CRD were assessed by measuring the abdominal with drawal reflex(AWR).The expression of SP in the ileocecal junction,colon,spinal cord of thoracic waist (T6-L5) and brain was detected by immunohistochemistry.Results The visceral pain induced by CRD produced a capacity-dependent increase of AWR score in normal saline group,and a dose-dependent reduction of AWR score in three of NaSH groups.There was no significant differences of SP expression in the ileocecal junction,colon,spinal cord of thoracic waist and thalamencepbalon between the normal saline group and the NaSH low dose group.However,the decreased SP expression in the NaSH moder- ate and high dose groups were observed in comparison to those in the normal saline group(P