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Activity‐dependent release and actions of endocannabinoids in the rat hypothalamic supraoptic nucleus
Author(s) -
Di Shi,
Boudaba Cherif,
Popescu Ion R.,
Weng FengJu,
Harris Christina,
Marcheselli Victor L.,
Bazan Nicolas G.,
Tasker Jeffrey G.
Publication year - 2005
Publication title -
the journal of physiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.802
H-Index - 240
eISSN - 1469-7793
pISSN - 0022-3751
DOI - 10.1113/jphysiol.2005.097477
Subject(s) - supraoptic nucleus , endocannabinoid system , parvocellular cell , neuroscience , magnocellular cell , postsynaptic potential , anandamide , excitatory postsynaptic potential , glutamate receptor , chemistry , retrograde signaling , medicine , biology , endocrinology , hypothalamus , inhibitory postsynaptic potential , microbiology and biotechnology , cannabinoid receptor , biochemistry , signal transduction , agonist , receptor
Exogenous cannabinoids have been shown to significantly alter neuroendocrine output, presaging the emergence of endogenous cannabinoids as important signalling molecules in the neuroendocrine control of homeostatic and reproductive functions, including the stress response, energy metabolism and gonadal regulation. We showed recently that magnocellular and parvocellular neuroendocrine cells of the hypothalamic paraventricular nucleus and supraoptic nucleus (SON) respond to glucocorticoids by releasing endocannabinoids as retrograde messengers to modulate the synaptic release of glutamate. Here we show directly for the first time that both of the main endocannabinoids, anandamide (AEA) and 2‐arachidonoyl glycerol (2‐AG), are released in an activity‐dependent fashion from the soma/dendrites of SON magnocellular neurones and suppress synaptic glutamate release and postsynaptic spiking. Cannabinoid reuptake blockade increases activity‐dependent endocannabinoid levels in the region of the SON, and results in the inhibition of synaptically driven spiking activity in magnocellular neurones. Together, these findings demonstrate an activity‐dependent release of AEA and 2‐AG that leads to the suppression of glutamate release and that is capable of shaping spiking activity in magnocellular neurones. This activity‐dependent regulation of excitatory synaptic input by endocannabinoids may play a role in determining spiking patterns characteristic of magnocellular neurones under stimulated conditions.