Linked Life Data

2765685

Source:http://linkedlifedata.com/resource/pubmed/id/2765685

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
1
pubmed:dateCreated
1989-9-27
pubmed:abstractText
Human anaphylatoxin C5a injected directly to the perifornical hypothalamus (PFH) of the rat elicits food intake in sated rats, an effect which mimics that of norepinephrine (NE) at the PFH. The ability of C5a to induce food intake is selectively blocked by the alpha-adrenergic antagonist phentolamine, confirming that C5a exerts its effects via an alpha-adrenergic receptor system. In this study specific C5a binding sites on rat brain slices were detected using 125I-C5a at 2.4 nM in the presence of unlabeled noncompeting C3a and competing C5a at 0.5 microM. To determine whether the in vivo activity of C5a was due to direct stimulation of an alpha-adrenergic receptor system or to indirect modulation via a specific C5a receptor, rats were pretreated at the PFH with C5ai, the "inactive" 74-desarginated derivative of C5a. C5ai blocked stimulation of feeding by C5a but had no effect on food intake elicited by NE, suggesting a presynaptic site for C5a activity. To determine whether C5a anaphylatoxin acts at presynaptic or postsynaptic sites, the ability of C5a and of NE to induce food intake in sated rats was compared before and after injection of the tyrosine hydroxylase inhibitor alpha-methyl-p-tyrosine (AMPT) to the PFH. AMPT would produce focal depletion of endogenous catecholamines by inhibition of catecholamine biosynthesis. Rats treated with AMPT failed to respond to C5a but ate excessively following NE, suggesting that C5a acts presynaptically, possibly to release NE. We propose that C5a acts at a specific C5a/C5ai receptor to modulate catecholamine activity at the brain site.
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Mar
pubmed:issn
0889-1591
pubmed:author
pubmed:issnType
Print
pubmed:volume
3
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
28-38
pubmed:dateRevised
2007-11-14
pubmed:meshHeading
pubmed:year
1989
pubmed:articleTitle
Binding specificity and presynaptic action of anaphylatoxin C5a in rat brain.
pubmed:affiliation
Manhattanville College, Purchase, New York 10577.
pubmed:publicationType
Journal Article, In Vitro, Research Support, U.S. Gov't, P.H.S.