Linked Life Data

15738275

Source:http://linkedlifedata.com/resource/pubmed/id/15738275

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
3
pubmed:dateCreated
2005-3-1
pubmed:abstractText
Reliable estimates of the quantum size in histaminergic neurons are not available. We have exploited two unusual opportunities in the fly's (Drosophila melanogaster) visual system to make such determinations for histaminergic photoreceptor synapses: 1) the possibility to microdissect successively from whole fly heads freeze-dried in acetone: the compound eyes; the first optic neuropils, or lamina; and the rest of the brain; and 2) the uniform sheaves of lamina synaptic terminals of photoreceptors R1-R6. We used this organization to count scrupulously the numbers of 30-nm synaptic vesicles from electron micrographs of R1-R6 profiles, and from microdissections we determined the regional contents of histamine in the compound eye, lamina, and central brain. Total head histamine averages 1.98 ng of which 9% was lost after freeze-drying in acetone and a further 28% after the brain was microdissected. Of the remainder, 71% was in the eye and lamina. Assuming that histamine loss from the tissue occurred mostly by diffusion evenly distributed among all regions, the overall lamina content of the head would be 0.1935 ng before dissection. From published values for the volumes of the brain's compartments, the computed regional concentrations of histamine are highest in the lamina (4.35 mM) because of the terminals of R1-R6. The concentration in the retina is approximately 13% that in the lamina, suggesting that most histamine is vesicular. There are approximately 43,500 +/- 7,400 (SD) synaptic vesicles per terminal and, if all histamine is allocated equally and exclusively among these, the vesicle contents would be 858 +/- 304 x 10(-21) moles or approximately 5,000 +/- 1,800 (SD) molecules at an approximate concentration of 670 mM. These values are compared with the vesicle contents at synapses using acetylcholine and catecholamines.
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Mar
pubmed:issn
0022-3077
pubmed:author
pubmed:issnType
Print
pubmed:volume
93
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
1611-9
pubmed:dateRevised
2008-11-21
pubmed:meshHeading
pubmed:year
2005
pubmed:articleTitle
Histamine compartments of the Drosophila brain with an estimate of the quantum content at the photoreceptor synapse.
pubmed:affiliation
Life Sciences Centre, Dalhousie University, 1355 Oxford St., Halifax, Nova Scotia, Canada B3H 4J1.
pubmed:publicationType
Journal Article, Comparative Study, Research Support, U.S. Gov't, P.H.S., Research Support, Non-U.S. Gov't