. Author manuscript; available in PMC: 2019 Jul 17.

Published in final edited form as: Nat Rev Neurosci. 2018 Jun;19(6):351–367. doi: 10.1038/s41583-018-0003-6

Table 1 |.

Selected markers of interneurons in the preBötzinger Complex

Marker	(Partially) overlapping markers^a	Relevance to, or effects on, preBötC interneurons	Refs
NK1R	SST and μOR	Peptide receptor that depolarizes (a subset of) rhythmogenic neurons; speeds up inspiratory rhythm	^{16,29,230,231}
μOR	NK1R	Peptide receptor that hyperpolarizes (a subset of) preBötC neurons; slows down inspiratory rhythm	^16,21
SST	NK1R, VGLUT2 and DBX1	Marker of pattern-generating output neurons (probably not rhythmogenic)	^{1,29,39,40,44,45,230}
Reelin	NK1R and SST	Marker for preBötC neurons and bulbospinal premotor neurons	³⁸
TRH	–	Peptide that depolarizes (a subset of) preBötC neurons; speeds up inspiratory rhythm	²⁵
VGLUT2	DBX1and SST	Marker for glutamatergic neurons that are essential for inspiratory rhythmogenesis	^40,44,45,232
DBX1	VGLUT2, SST, SSTR2A and NK1R	Transcription factor expressed by glutamatergic rhythmgenerating neurons, premotor neurons and midbrain- projecting neurons	^{10,12,44,45,169,233}
NMBR or GRPR	SST	Peptide receptors that induce sighs	¹⁸⁹
CDH9	DBX1	Marker for neurons that project to the (locus coeruleus within the) pons that are potentially involved in arousal	¹²

μOR, μ-opioid receptor; CDH9, cadherin 9; DBX1, developing brain homeobox protein 1; GRPR, gastrin-releasing peptide receptor; NK1R, neurokinin 1 receptor; NMBR, neuromedin B receptor; preBötC, preBötzinger Complex; SST, somatostatin; SST2AR, somatostatin 2A receptor; TRH, thyrotropin-releasing hormone; VGLUT2, vesicular glutamate transporter 2.

Interneuron populations defined by individual markers overlap to varying degrees with other populations.