RT Journal Article
SR Electronic
T1 Developmental Regulation of a Local Positive Autocontrol of Supraoptic Neurons
JF The Journal of Neuroscience
JO J. Neurosci.
FD Society for Neuroscience
SP 5813
OP 5819
DO 10.1523/JNEUROSCI.20-15-05813.2000
VO 20
IS 15
A1 Vivien Chevaleyre
A1 Govindan Dayanithi
A1 Françoise C. Moos
A1 Michel G. Desarménien
YR 2000
UL http://www.jneurosci.org/content/20/15/5813.abstract
AB Mature oxytocin (OT) and vasopressin (AVP) magnocellular neurons of the hypothalamic supraoptic nuclei (SON) autocontrol their electrical activity via somatodendritic release of their respective peptides. Because OT and AVP are synthesized early in development and could play an important role in the maturation of these neurons, we checked whether the peptides are released within the SON and act on their secreting neurons during 3 weeks of postnatal development. We used patch-clamp recordings from SON neurons in rat hypothalamic horizontal slices to show that the spontaneous electrical activity of immature SON neurons is blocked by OT or AVP receptor antagonists, demonstrating a basal somatodendritic release of the peptides. Application of OT or AVP depolarizes SON neurons and stimulates activity typical of the corresponding mature neurons. This effect is directly on SON neurons because it is recorded in dissociated neurons. Radioimmunoassays from isolated SON were used to show that each peptide facilitates its own release at a somatodendritic level, exhibiting a self-sustaining positive feedback loop. This autocontrol is not uniform during development because the proportion of neurons depolarized by the peptides, the amplitude of the depolarization, and the propensity of the peptides to facilitate their own release are maximal during the second postnatal week and decrease thereafter. These data are consistent with a role of autocontrol in the maturation of SON neurons because it is maximal during the delimited period of postnatal development that corresponds to the period of major synapse formation.