Table 1.
Membrane receptors expressed on phrenic motoneurons.
| Receptor Class | Subtypes/Isoforms | Function * | References |
|---|---|---|---|
| AMPA | Glur1 | Fast excitatory neurotransmission | (Robinson and Ellenberger, 1997) |
| Glur2 | Fast excitatory neurotransmission | (Robinson and Ellenberger, 1997) | |
| NMDA | NR1 | Excitatory neurotransmission; neuroplasticity | (Robinson and Ellenberger, 1997) |
| NR2A | Excitatory neurotransmission; neuroplasticity | (Alilain and Goshgarian, 2008) | |
| Kainate | Glur5–7 | Excitatory neurotransmission | (Robinson and Ellenberger, 1997) |
| mGluR | Group I-III | Modulates synaptic transmission | (Dong and Feldman, 1999) |
| Serotonin | 5-HT1a | Modulate PhrMN excitability | (Pecotic et al., 2009) |
| 5-HT1b | Modulate PhrMN excitability | (Bras et al., 2008) | |
| 5-HT2a | Modulate PhrMN excitability; Initiate phrenic motor plasticity | (Basura et al., 2001) | |
| 5-HT2c | Initiate phrenic motor plasticity | (Basura et al., 2001) | |
| 5-HT7 | Initiate phrenic motor plasticity | (Fields et al., 2015) | |
| Adenosine | A2A | Initiate phrenic motor plasticity | (Seven et al., 2018b) |
| 1 | Antagonism enhances phrenic recovery following spinal injury | (Nantwi et al., 2003) | |
| TrkB | TrkB.T1 / TrkB.T2 | Competitively inhibit Trk signaling | (Gransee et al., 2013) |
| TrkB.FL | Synaptic plasticity | (Mantilla et al., 2013) | |
| GABA | GABA-A | Inhibitory neurotransmission | (Chitravanshi and Sapru, 1999) |
| GABA-B | Inhibitory neurotransmission | (Lalley, 1983) | |
| Glycine | Glycine | Inhibitory neurotransmission | (Marchenko and Rogers, 2009) |
| nACHR | α7 | Nicotinic cholinergic neurotransmission | (Dehkordi et al., 2004) |
| ATP | P2X1 | Impacts PhrMN excitability | (Miles et al., 2002) |
| P2X2 | Impacts PhrMN excitability | (Miles et al., 2002) | |
| P2X5 | Impacts PhrMN excitability | (Miles et al., 2002) | |
| P2Y1 | Impacts PhrMN excitability | (Alvares et al., 2014) | |
| VEGFR | VEGFR2 | Evoke phrenic motor plasticity | (Dale-Nagle et al., 2011) |
| Erythropoietin | EPOR | Evoke phrenic motor plasticity | (Dale et al., 2012) |
| Peptide | NK-1 | Mediate substance p transmission | (Holtman et al., 1984) |
| Estrogen | alpha (ERa) | Modulate PhrMN output | (Behan and Thomas, 2005) |
| (ERβ) | Modulate PhrMN output | (Behan and Thomas, 2005) | |
| Androgen | AR | Modulate PhrMN output | (Behan and Thomas, 2005) |
| Adrenergic | α1 | Synaptic plasticity | (Snider and Gerald, 1982) |
regarding function: in some cases (e.g., AMPA, GABA), the precise function of the receptor is clear; in other cases the precise role can be speculated but not definitively stated (e.g., "modulate PhrMN output).
Abbreviations: α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA), Glutamate receptor 1 (Glurl), Glutamate receptor 2 (Glur2), N-methyl-D-aspartate (NMDA), N-methyl-D- aspartate receptor subunit 1 (NR1), N-methyl-D-aspartate receptor subunit 2A (NR2A), Glutamate receptor 5 (Glur5), Metabotropic glutamate receptors (mGlurR), 5-hydroxytryptamine receptor 1a (5-HTR1a), 5-hydroxytryptamine receptor 1b (5-HTR1b), 5-hydroxytryptamine receptor 2a (5-HTR2a), 5-hydroxytryptamine receptor 2c (5-HTR2c), Adenosine receptor 2A (A2A), Adenosine receptor 1 (A1), Tropomyosin receptor kinase B (TrkB), Truncated TrkB receptor 1 (TrkB.T1), Truncated TrkB receptor 2 (TrkB.T2), Full length TrkB receptor (TrkB.FL), Gamma aminobutyric acid receptor (GABA), Gamma aminobutyric acid receptor A (GABA-A), Gamma aminobutyric acid receptor B (GABA-B), Nicotinic acetylcholine receptors (nAChR), Alpha7 nicotinic acetylcholine receptor (nACHR-α7), Purinergic receptor 2X1 (P2X1), Purinergic receptor 2X2 (P2X2), Purinergic receptor 2X5 (P2X5), Purinergic receptor 2Y1 (P2Y1), Vascular endothelial growth factor receptor (VEGFR), Vascular endothelial growth factor receptor 2 (VEGFR2), Erythropoietin receptor (EPOR), Neurokinin-1 receptor (NK-1), Estrogen alpha receptor (ERα), Estrogen beta receptor (ERβ), Androgen receptor (AR), Adrenergic α1 receptor (α1)