Spontaneous outward currents expressed preferentially in inhibitory neurons in the rat prepositus hypoglossi nucleus

2011 ◽  
Vol 71 ◽  
pp. e144
Author(s):  
Yasuhiko Saito ◽  
Yuchio Yanagawa
Keyword(s):  
Inhibitory Neurons ◽  
Outward Currents ◽  
Prepositus Hypoglossi ◽  
Spontaneous Outward Currents

Ca2+-activated ion currents triggered by ryanodine receptor-mediated Ca2+release control firing of inhibitory neurons in the prepositus hypoglossi nucleus

2013 ◽  
Vol 109 (2) ◽  
pp. 389-404 ◽  
Author(s):  
Yasuhiko Saito ◽  
Yuchio Yanagawa
Keyword(s):  
Ryanodine Receptors ◽  
Smooth Muscles ◽  
Firing Frequency ◽  
Neuronal Firing ◽  
Inhibitory Neurons ◽  
Sk Channels ◽  
Spontaneous Firing ◽  
Central Neurons ◽  
Outward Currents ◽  
Prepositus Hypoglossi

Spontaneous miniature outward currents (SMOCs) are known to exist in smooth muscles and peripheral neurons, and evidence for the presence of SMOCs in central neurons has been accumulating. SMOCs in central neurons are induced through Ca2+-activated K+(KCa) channels, which are activated through Ca2+-induced Ca2+release from the endoplasmic reticulum via ryanodine receptors (RyRs). Previously, we found that some neurons in the prepositus hypoglossi nucleus (PHN) showed spontaneous outward currents (SOCs). In the present study, we used whole cell recordings in slice preparations of the rat brain stem to investigate the following: 1) the ionic mechanisms of SOCs, 2) the types of neurons exhibiting frequent SOCs, and 3) the effect of Ca2+-activated conductance on neuronal firing. Pharmacological analyses revealed that SOCs were induced via the activation of small-conductance-type KCa(SK) channels and RyRs, indicating that SOCs correspond to SMOCs. An analysis of the voltage responses to current pulses of the fluorescence-expressing inhibitory neurons of transgenic rats revealed that inhibitory neurons frequently exhibited SOCs. Abolition of SOCs via blockade of SK channels enhanced the frequency of spontaneous firing of inhibitory PHN neurons. However, abolition of SOCs via blockade of RyRs reduced the firing frequency and hyperpolarized the membrane potential. Similar reductions in firing frequency and hyperpolarization were also observed when Ca2+-activated nonselective cation (CAN) channels were blocked. These results suggest that, in inhibitory neurons in the PHN, Ca2+release via RyRs activates SK and CAN channels, and these channels regulate spontaneous firing in a complementary manner.

Membrane properties of excitatory and inhibitory neurons in the rat prepositus hypoglossi nucleus

2008 ◽  
Vol 27 (9) ◽  
pp. 2413-2424 ◽  
Author(s):  
Masato Shino ◽  
Seiji Ozawa ◽  
Nobuhiko Furuya ◽  
Yasuhiko Saito
Keyword(s):  
Inhibitory Neurons ◽  
Membrane Properties ◽  
Prepositus Hypoglossi

scholarly journals Implications of Extended Inhibitory Neuron Development

2021 ◽  
Vol 22 (10) ◽  
pp. 5113
Author(s):  
Jae-Yeon Kim ◽  
Mercedes F. Paredes
Keyword(s):  
Neural Circuit ◽  
Inhibitory Neuron ◽  
Postnatal Period ◽  
Specific Pattern ◽  
Inhibitory Neurons ◽  
Gabaergic Interneuron ◽  
Gabaergic Interneurons ◽  
Neuron Development ◽  
Cortical Regions ◽  
Circuit Formation

A prolonged developmental timeline for GABA (γ-aminobutyric acid)-expressing inhibitory neurons (GABAergic interneurons) is an amplified trait in larger, gyrencephalic animals. In several species, the generation, migration, and maturation of interneurons take place over several months, in some cases persisting after birth. The late integration of GABAergic interneurons occurs in a region-specific pattern, especially during the early postnatal period. These changes can contribute to the formation of functional connectivity and plasticity, especially in the cortical regions responsible for higher cognitive tasks. In this review, we discuss GABAergic interneuron development in the late gestational and postnatal forebrain. We propose the protracted development of interneurons at each stage (neurogenesis, neuronal migration, and network integration), as a mechanism for increased complexity and cognitive flexibility in larger, gyrencephalic brains. This developmental feature of interneurons also provides an avenue for environmental influences to shape neural circuit formation.

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