The effects of apelin on the electrical activity of hypothalamic magnocellular vasopressin and oxytocin neurons and somato/dendritic peptide release

VA Tobin, PM Bull, S Arunachalam, A-M O'Carroll, Y Ueta, M Ludwig

Research output: Contribution to journalArticle (Academic Journal)peer-review

45 Citations (Scopus)

Abstract

Apelin, a novel peptide originally isolated from bovine stomach tissue extracts, is widely but selectively distributed throughout the nervous system. Vasopressin and oxytocin are synthesized in the magnocellular neurons of the hypothalamic supraoptic nucleus (SON) and paraventricular nucleus, which are apelin-rich regions in the central nervous system. We made extracellular electrophysiological recordings from the transpharyngeally exposed SON of urethane-anaesthetized rats to assess the role of apelin in the control of the firing activity of identified magnocellular vasopressin and oxytocin neurons in vivo. Apelin-13 administration onto SON neurons via microdialysis revealed cell-specific responses; apelin-13 increased the firing rates of vasopressin cells but had no effect on the firing rate of oxytocin neurons. A direct excitatory effect of apelin-13 on vasopressin cell activity is also supported by our in vitro studies showing depolarization of membrane potential and increase in action potential firing. To assess the effects of apelin-13 on somatodendritic peptide release, we used in vitro release studies from SON explants in combination with highly sensitive and specific RIA. Apelin-13 decreases basal (by 78%; P < 0.05; n = 6) and potassium-stimulated (by 57%; P < 0.05; n = 6) vasopressin release but had no effect on somatodendritic oxytocin release. Taken together, our data suggest a local autocrine feedback action of apelin on magnocellular vasopressin neurons. Furthermore, these data show a marked dissociation between axonal and dendritic vasopressin release with a decrease in somatodendritic release but an increase in electrical activity at the cell bodies, indicating that release from these two compartments can be regulated wholly independently.
Translated title of the contributionThe effects of apelin on the electrical activity of hypothalamic magnocellular vasopressin and oxytocin neurons and somato/dendritic peptide release
Original languageEnglish
Pages (from-to)6136 - 6145
Number of pages10
JournalEndocrinology
Volume149
Issue number12
Early online date14 Aug 2008
DOIs
Publication statusPublished - 1 Dec 2008

Fingerprint

Dive into the research topics of 'The effects of apelin on the electrical activity of hypothalamic magnocellular vasopressin and oxytocin neurons and somato/dendritic peptide release'. Together they form a unique fingerprint.

Cite this