The Rostral Agranular Insular Cortex, a New Site of Oxytocin to Induce Antinociception
Por:
Gamal-Eltrabily, Mohammed, Espinosa de los Monteros-Zuniga, Antonio, Manzano-Garcia, Alfredo, Martinez-Lorenzana, Guadalupe, Condes-Lara, Miguel, Gonzalez-Hernandez, Abimael
Publicada:
15 jul 2020
Categoría:
Neuroscience (miscellaneous)
Resumen:
The rostral agranular insular cortex (RAIC) is a relevant structure in
nociception. Indeed, recruitment of GABAergic activity in RAIC promotes
the disinhibition of the locus ceruleus, which in turn inhibits (by
noradrenergic action) the peripheral nociceptive input at the spinal
cord level. In this regard, at the cortical level, oxytocin can modulate
the GABAergic transmission; consequently, an interaction modulating
nociception could exist between oxytocin and GABA at RAIC. Here, we
tested in male Wistar rats the effect of oxytocin microinjection into
RAIC during an inflammatory (by subcutaneous peripheral injection of
formalin) nociceptive input. Oxytocin microinjection produces a
diminution of (1) flinches induced by formalin and (2) spontaneous
firing of spinal wide dynamic range cells. The above antinociceptive
effect was abolished by microinjection (at RAIC) of the following: (1)
L-368899 (an oxytocin receptor [OTR] antagonist) or by (2) bicuculline
(a preferent GABA A receptor blocker), suggesting a GABAergic activation
induced by OTR. Since intrathecal injection of an alpha(2A)-adrenoceptor
antagonist (BRL 44408) partially reversed the oxytocin effect, a
descending noradrenergic antinociception is suggested. Further,
injection of L-368899 per se induces a pronociceptive behavioral effect,
suggesting a tonic endogenous oxytocin release during inflammatory
nociceptive input. Accordingly, we found bilateral projections from the
paraventricular nucleus of the hypothalamus (PVN) to RAIC. Some of the
PVN-projecting cells are oxytocinergic and destinate GABAergic and
OTR-expressing cells inside RAIC. Aside from the direct anatomic link
between PVN and RAIC, our findings provide evidence about the role of
oxytocinergic mechanisms modulating the pain process at the RAH: level.
Filiaciones:
Gamal-Eltrabily, Mohammed:
Univ Nacl Autonoma Mexico, Inst Neurobiol, Campus UNAM Juriquilla, Juriquilla 76230, Mexico
Espinosa de los Monteros-Zuniga, Antonio:
Univ Nacl Autonoma Mexico, Inst Neurobiol, Campus UNAM Juriquilla, Juriquilla 76230, Mexico
Manzano-Garcia, Alfredo:
Univ Nacl Autonoma Mexico, Inst Neurobiol, Campus UNAM Juriquilla, Juriquilla 76230, Mexico
Martinez-Lorenzana, Guadalupe:
Univ Nacl Autonoma Mexico, Inst Neurobiol, Campus UNAM Juriquilla, Juriquilla 76230, Mexico
Condes-Lara, Miguel:
Univ Nacl Autonoma Mexico, Inst Neurobiol, Campus UNAM Juriquilla, Juriquilla 76230, Mexico
Gonzalez-Hernandez, Abimael:
Univ Nacl Autonoma Mexico, Inst Neurobiol, Campus UNAM Juriquilla, Juriquilla 76230, Mexico
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