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Electrophysiological Properties of TRPV1‐Expressing Neurons in the Paraventricular Nucleus of the Hypothalamus
Author(s) -
Butcher Sierra Morgan,
Miyata Kayoko,
Anwar Imran John,
Zsombok Andrea
Publication year - 2016
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.30.1_supplement.1248.4
Subject(s) - trpv1 , excitatory postsynaptic potential , electrophysiology , postsynaptic current , neurotransmission , patch clamp , inhibitory postsynaptic potential , chemistry , hypothalamus , neuroscience , postsynaptic potential , nucleus , medicine , endocrinology , microbiology and biotechnology , biophysics , biology , transient receptor potential channel , receptor , biochemistry
Whole body glucose homeostasis is regulated throughperipheral and central mechanisms, and transient receptor potential vanilloidtype 1 (TRPV1) has been shown to play a role in modulation of glucosehomeostasis. Previously, our datarevealed that liver‐related neurons in the paraventricular nucleus (PVN) of thehypothalamus are regulated by TRPV1‐dependent excitatory neurotransmission, which was diminished in diabetic condition. In this study, a reporter mousemodel was established (TRPV1 TdTomato ) to identify the location, determinethe cellular properties, and phenotype of TRPV1‐expressing cells. Within the hypothalamus, TRPV1 TdTomato cellswere observed in the PVN, dorsomedial, and lateral hypothalamus. Whole‐cell patch‐clamp electrophysiology wasused to establish the cellular properties of TRPV1 TdTomato neuronsin the PVN. The average frequency of spontaneousexcitatory postsynaptic currents (sEPSCs) was 2.38 ± 0.6 Hz, with an averageamplitude of 15.83 ± 1.8 pA (n=15). Frequency of miniature EPSCs (mEPSCs) averaged 1.79 ± 0.4 Hz, with an amplitude of 15.66 ± 2.7 pA (n=12). The frequency of spontaneous inhibitory postsynaptic currents (sIPSCs)was 2.37 ± 0.6 Hz, while the average amplitude was 37.61 ± 5.2 pA (n=12). The average frequency of miniature IPSCs (mIPSCs)was 1.44 ± 0.4 Hz, with an amplitude of 31.92 ± 4.6 pA (n=9). The frequency and amplitude of EPSCs andIPSCs recorded from TRPV1 TdTomato PVN neurons were similar to thosepreviously recorded from liver‐related and kidney‐related PVN neurons. TRPV1 TdTomato neurons fired actionpotentials spontaneously, the firing rate was 1.50 ± 0.44 Hz (n=6) and theinput resistance was 2.06 ± 0.66 GΩ. To determine the phenotype of TRPV1 TdTomato neurons, immunostaining for neuronal cell type markers and an astrocyte marker wasperformed. Our data did not reveal co‐localization with vasopressin, oxytocin, orthe astrocyte marker, suggesting that TRPV1 TdTomato cells are notmagnocellular neurons or astrocytes. Insummary, the TRPV1 TdTomato mouse model is a useful tool to study therole of TRPV1 in autonomic control; however, further studies are necessary todetermine their phenotype and cellular properties in control and diabeticconditions. Support or Funding Information National Institutes of Health (R01 DK099598 for AZ)