C-type natriuretic peptide (CNP) shows remarkable sequence homology to atrial natriuretic peptide (ANP) and B-type natriuretic peptide (BNP) within the 17-residue ring portion formed by a pair of cysteine residues and being the third member of the natriuretic peptide family. Sequence analysis reveals that there are at least two exons in the coding region for preproCNP. Mature forms of CNP in body are CNP22 and its N-termi-nally elongated form CNP53. As an agonist, CNP selectively bind to natriuretic peptide receptor B (NPR-B) which has a single member-spanning helical domain and exert its biological effects by activating its C-teminal guanylate cyclase to catalyse formation of cyclic guanosine monophosphate (cGMP). CNP can also bind to natriuretic peptidereceptor C (NPR-C) which has high binding affinities for all of the natriuretic peptides. The synthesis and release of CNP are regulated by many cy-tokines, and CNP is metabolized by two main pathways : internalization and degradation through the binding with NPR-C or hydrolysis by neutral endopeptidase. CNP and its receptor distribute widespreadly in various tissues including vessels, blood and central neural systems, and produce effects of vasodilation, antianxiely effect and regulations of cell proliferation and endocrine.

The present study was to investigate the analgesic effect and mechanism of meto-clopramide (MCP) on a rabbit visceral pain model. The results showed that MCP (8 mg? kg-1,iv) could produce a significant analgesic effect on visceral pain (P

Objective: To explore the relationship between parental control and aggressive behavior of middle school students. Methods: Random cluster sampling was used to select 1 046 students.Information was collected through the Chinese version of Parental Control Questionnaire and Buss ＆ Perry Aggression Questionnaire. Results: The score on anger were high among female students and the total score were high among male students(t=6.28,2.56,P<0.01).Multiple comparison showed. the grade two junior middle school students’aggression level is significantly higher than grade three junior middle school students and grade one, two high school students(t=3.22,4.07,3.01,P<0.05). There were significant gender differences in parental control,father’s behavior control and father’s psychological control(P<0.05).Parental control shows a significant grade difference,multiple comparison showed, parental control among junior middle school students is significantly higher than that among high school students(t=3.22, 4.07, 3.01, P<0.05).Parental control and aggressiveness of the students were significantly positively correlated(r=0.16,0.29).There was a significant positive correlation between the psychological control of the parents and the aggressiveness of the boys(r=0.26,0.23).The behavior control and psychological control of the parents were positively correlated with the aggressiveness of the girls(r=0.09,0.13,0.29,0.35)(P<0.05).The Logistic regression analysis showed,father’s psychological control(OR=0.50,95%CI=0.21-0.79) and mother’s psychological control(OR=0.32,95%CI=0.02-0.62) showed significant positive association with aggression of the boys.Mother’s psychological control(OR=0.55,95%CI=0.23-0.87)and parents’ control(OR=0.17,95%CI=0.01-0.33) were positively associated with aggression of the girls(P<0.05). Conclusion Effective intervention of parental control might help prevent and control aggressive behavior of middle school students.