Loading…
NMDA receptors induce somatodendritic secretion in hypothalamic neurones of lactating female rats
Many neurones in the mammalian brain are known to release the content of their vesicles from somatodendritic locations. These vesicles usually contain retrograde messengers that modulate network properties. The back-propagating action potential is thought to be the principal physiological stimulus t...
Saved in:
Published in: | The Journal of physiology 2004-11, Vol.561 (1), p.53-64 |
---|---|
Main Authors: | , , , , |
Format: | Article |
Language: | English |
Subjects: | |
Citations: | Items that this one cites Items that cite this one |
Online Access: | Get full text |
Tags: |
Add Tag
No Tags, Be the first to tag this record!
|
Summary: | Many neurones in the mammalian brain are known to release the content of their vesicles from somatodendritic locations. These
vesicles usually contain retrograde messengers that modulate network properties. The back-propagating action potential is
thought to be the principal physiological stimulus that evokes somatodendritic release. In contrast, here we show that calcium
influx through NMDA receptor (NMDAR) channels, in the absence of postsynaptic cell firing, is also able to induce vesicle
fusion from non-synaptic sites in nucleated outside-out patches of dorsomedial supraoptic nucleus (SON) neurones of adult
female rats, in particular during their reproductive stages. The physiological significance of this mechanism was characterized
in intact brain slices, where NMDAR-mediated release of oxytocin was shown to retrogradely inhibit presynaptic GABA release,
in the absence of postsynaptic cell firing. This implies that glutamatergic synaptic input in itself is sufficient to elicit
the release of oxytocin, which in turn acts as a retrograde messenger leading to the depression of nearby GABA synapses. In
addition, we found that during lactation, when oxytocin demand is high, NMDA-induced oxytocin release is up-regulated compared
to that in non-reproductive rats. Thus, in the hypothalamus, local signalling back and forth between pre- and postsynaptic
compartments and between different synapses may occur independently of the firing activity of the postsynaptic neurone. |
---|---|
ISSN: | 0022-3751 1469-7793 |
DOI: | 10.1113/jphysiol.2004.069005 |