Linked Life Data

2576042

Source:http://linkedlifedata.com/resource/pubmed/id/2576042

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
11
pubmed:dateCreated
1990-3-26
pubmed:abstractText
Morphine and the opioid peptides cause isolated segments of rat colon to contract and relax rhythmically. This study re-examines two hypotheses to explain this phenomenon: Release of 5-hydroxytryptamine (5-HT)/acetylcholine by morphine or inhibition of a tonically active non-adrenergic, non-cholinergic (NANC) inhibitory mechanism. Rhythmic contractions induced by morphine (5 x 10(-6) M) were naloxone sensitive (10(-6) M) but unaffected by methysergide (10(-6) M), atropine (10(-6) M) or pretreatment of rats with p-chlorophenylalanine (200 mg kg-1 i.p. for four days) which lowered the 5-HT level in the colon from 3.73 +/- 0.83 mg g-1 in controls to 0.41 +/- 0.06 mg g-1 (P less than 0.001). The pattern of rhythmic contractions produced by morphine was unlike those produced by 5-HT (5 x 10(-6) M), acetylcholine (5 x 10(-6) M) or potassium chloride (30 mM). Tetrodotoxin (10(-6) M), apamin (10(-8) M), clonidine (2 x 10(-8) M), phentolamine (10(-5) M) or oxprenolol (10(-5) M) caused rhythmic contractions which were unaffected by naloxone. Clonidine contractions were inhibited by yohimbine (10(-7) M) but not by prazosin (10(-6) M). Electrical field stimulation at the peak of a contraction induced by morphine, apamin or clonidine, produced an inhibitory response which was unaffected by atropine, phentolamine, propranolol and guanethidine (all 10(-5) M). It persisted in colon segments from the rats with reserpine or 6-hydroxydopamine. These results suggest that neither the 5-HT/acetylcholine hypothesis nor inhibition of the NANC mechanism adequately explains the excitatory effect of morphine in the rat colon.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Nov
pubmed:issn
0022-3573
pubmed:author
pubmed:issnType
Print
pubmed:volume
41
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
751-6
pubmed:dateRevised
2006-11-15
pubmed:meshHeading
pubmed:year
1989
pubmed:articleTitle
Excitatory effect of morphine and opioid peptides in the rat isolated colon.
pubmed:affiliation
Department of Pharmacology, University of Glasgow, UK.
pubmed:publicationType
Journal Article, In Vitro, Research Support, Non-U.S. Gov't