In Vitro Study of Acetylcholine and Histamine Induced Contractions in Colon and Rectum of Adult and Neonate Rats.
Loading...
Date
2013-04
Authors
Journal Title
Journal ISSN
Volume Title
Publisher
Abstract
Contractile mechanisms of different parts of the gut in adult
and neonate may not be identical due to developmental processes. The
present study was undertaken to investigate acetylcholine (ACh) and
histamine induced contractile responses of colon and rectum in adult and
neonatal albino rats. Contractile responses were recorded from isolated in
vitro preparations. The dose-response curve for ACh (0.001-100 μM) revealed
dose dependent increase in contractile responses. A significantly (P<0.05)
greater contractile responses (g/g wet tissue) was observed in rectum as
compared to colon. Atropine pretreatment significantly blocked ACh
responses in both rectum and colon. The blockade was higher in adult
preparations. The dose-response study for histamine (0.001-100 μM) did not
show any significant difference between rectum and colon. Histamine
(100 μM) induced contractions were significantly (P<0.05) increased after
pretreatment with pheniramine (100 μM) in adult rectum. This potentiating
response of pheniramine was absent in neonate rectum. Such effect was
also not seen in colon of both adult and neonate. The present investigation
indicates that the contractile responses induced by ACh are similar in both
adult and neonate, excepting that the blocking effect of atropine in colon
was more pronounced in adult as compared to neonate. Further, the results
also indicated different mechanism of histamine action in adults and neonates
as evidenced by the significant enhancement of contractions by pheniramine
only in adult rectum. Therefore, the present results indicate the existence
of a different cholinergic and histaminergic activity in adult and neonate
as well as in rectal and colonic tissue.
Description
Keywords
acetylcholine, histamine, neonate rectum, colon rat
Citation
Singh Shuchita, Mandal Maloy B. In Vitro Study of Acetylcholine and Histamine Induced Contractions in Colon and Rectum of Adult and Neonate Rats. Indian Journal of Physiology and Pharmacology. 2013 Apr-Jun; 57(2): 104-113.