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Angiotensin II inhibits GABAergic synaptic transmission in dorsolateral periaqueductal gray
Author(s) -
Lu Jian,
Xing Jihong,
Li Jianhua
Publication year - 2008
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.22.1_supplement.1168.6
Subject(s) - excitatory postsynaptic potential , inhibitory postsynaptic potential , chemistry , neurotransmission , gabaergic , endocrinology , losartan , medicine , angiotensin ii , periaqueductal gray , postsynaptic current , neuroscience , receptor , biology , central nervous system , midbrain
The purpose of this study was to determine the role of angiotensin II (Ang II) in modulating inhibitory and excitatory synaptic inputs to the dorsolateral periaqueductal gray (dl‐PAG). Whole cell voltage‐clamp recording was performed to obtain inhibitory and excitatory postsynaptic currents (IPSCs and EPSCs) of the dl‐PAG neurons. Application of Ang II, in the concentration of 2 μM, decreased the amplitude of evoked IPSCs from 148±15 to 89±7 pA in eight tested neurons ( P <0.05). The paired‐pulse ratio (PPR) of evoked IPSCs was also examined, and increased by 96±5% in control and by 125±7% after Ang II ( P <0.05 vs. control). Additionally, Ang II decreased the frequency of miniature IPSCs from 0.83±0.02 to 0.45±0.03 Hz in ten tested neurons ( P <0.05) without affecting the amplitude and the decay time constant. The effect of Ang II on miniature IPSCs was blocked by Losartan (an Ang II AT1 receptor antagonist), but not by PD123319 (an AT2 receptor antagonist). In contrast, Ang II wasn't observed to have distinct effects on the EPSCs. The data presented in this study provide strong evidence indicating that Ang II inhibits GABAergic synaptic inputs to the dl‐PAG through activation of presynaptic AT1 receptors (Supported by R01 HL075533, R01 HL078866 & R01 HL060800).