Linked Life Data

7931572

Source:http://linkedlifedata.com/resource/pubmed/id/7931572

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
10
pubmed:dateCreated
1994-11-14
pubmed:abstractText
The mu-opioid agonist DAMGO (Tyr-D-Ala-Gly-MePhe-Gly-ol) hyperpolarizes the majority of arcuate hypothalamic (ARC) neurons by opening an inwardly rectifying potassium conductance. The EC50 for the DAMGO-induced hyperpolarization was 60 +/- 3 nM in ARC neurons from ovariectomized guinea pigs. Superfusion of 17 beta-estradiol (E2; 100 nM) for 20 min in vitro resulted in a significant decrease in DAMGO potency (EC50 = 212 +/- 16 nM) in 40% of the neurons that were tested. This rapid effect of E2 on the mu-opioid response was not mimicked by the biologically inactive isomer 17 alpha-estradiol. Multiple concentrations of E2 were used to generate an E2 concentration-response curve, with an EC50 of 9 nM and a maximal increase in the DAMGO EX50 of 411% of controls. The membrane properties and firing rate of E2-sensitive and E2-insensitive neurons were not different. Streptavidin-FITC labeling did not reveal any significant morphological differences between the groups, but a higher number of E2-sensitive cells was found in the lateral ARC and cell-poor zone. Moreover, immunocytochemical staining of the recorded cells revealed that beta-endorphin neurons were among those sensitive to E2. Therefore, E2 could increase beta-endorphin release by decreasing the potency of beta-endorphinergic autoinhibition, thus increasing the tonic opioid inhibition of E2-insensitive cells. Furthermore, the diffuse projections of hypothalamic beta-endorphin neurons would allow E2 to alter processes throughout the brain, as well as having local effects in the hypothalamus.
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Oct
pubmed:issn
0270-6474
pubmed:author
pubmed:issnType
Print
pubmed:volume
14
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
6196-204
pubmed:dateRevised
2007-11-14
pubmed:meshHeading
pubmed:year
1994
pubmed:articleTitle
The potency of mu-opioid hyperpolarization of hypothalamic arcuate neurons is rapidly attenuated by 17 beta-estradiol.
pubmed:affiliation
Department of Physiology, Oregon Health Sciences University, Portland 97201-3098.
pubmed:publicationType
Journal Article, In Vitro, Research Support, U.S. Gov't, P.H.S.