Type: Sensory neuron (oxygen- and minor CO₂-sensory)
In MoW: PQR
Male Wiring Project: PQR
In Wormbase: PQR
Lineage: QL.ap
Location: Left Lumbar ganglia
Description: Postembryonically born from the left Q neuroblast (QL) and migrates posteriorly to a position near the phasmid neurons in the left lumbar ganglion. Single neuron with basal body. It is directly exposed to the pseudocoelomic body fluid (internal environment of the animal). An anterior process projects into preanal gangion and usually ends just posterior to the vulva, although can be slightly shorter or longer. Posterior process is ensheathed by PHso2L cell.
See a 3-D reconstruction of PQR by R. Newbury & Moerman lab. (Cell labels are shown below. 3-D movie was created from confocal images of a strain expressing the GFP marker linked to the promoter for ZC53.7 using Zeiss LSM 5 Pascal software v. 3.2).

Neurotransmitter/Neuropeptide:
- Glutamate
(Pereira et al., 2015)
Innexin expression:
None yet reported, although described to have gap junctions in adult animals (MoW)
Receptor expression:
- GCY-32; guanylyl cyclase
- GCY-35; guanylyl cyclase which binds molecular oxygen and mediates oxygen sensation
- NPR-1; neuropeptide Y receptor like protein
- PDFR-1; pigment dispersing factor receptor ortholog
(Barrios et al, 2012; Gray et al., 2004; Coates and de Bono, 2002; Yu et al., 1997)
Function:
- Functions in aerotaxis, and along with AQR, URX and AUA regulate social feeding (or aggregation on a bacterial lawn) and bordering(the accumulation of animals on the thickest part of a bacterial lawn) behavior. Suppressing the activity of AQR, PQR and URX neurons inhibits social feeding (Coates and de Bono , 2002). AQR, PQR and URX function as sensors of environmental oxygen which is a quantitative regulator of social feeding (Gray et al., 2004). Studies indicate that animals that carry the npr-1 (215F) allele or that lack npr-1 function tend to dwell (slow down) in low ambient O₂ and roam (disperse) or aggregate in high ambient O₂. In this model, drops in O₂ lead to increased activity of a GCY-35/GCY-36 heterodimeric soluble guanylate cyclase. Rising cGMP, in turn, opens the TAX-2/TAX-4 cGMP-gated ion channel in AQR, PQR and URX leading to their depolarization and when the food is present, strong suppression of roaming behavior (Cheung et al., 2005). In npr-1 mutants these neurons are thought to be hyperactive (see URX page for a full description).
- AQR, PQR and URX suppress innate immunity via NPR-1, which regulates both PMK-1-dependent and PMK-1-independent immune responses (Styer et al., 2008). Since URX , AQR, PQR are exposed to pseudocoelomic fluid, they are hypothesized to communicate neuroendocrine signals to nonneural tissues involved in innate immunity defense responses.
- AQR, PQR and URX are weak CO₂-sensors and contribute to CO2 avoidance (main CO₂ sensors are AFD, BAG and ASE) (Bretscher et al., 2011)
- Part of the neuronal circuit that functions in mate-searching behavior of males (Barrios et al, 2012)