Type: Sensory neuron (oxygen- and minor CO2-sensory)
In WormWiring: AQRh, AQRm,
In Wormbase: AQR
Lineage: QR.ap
Location: Head; right side near the posterior bulb of the pharynx.
Description: Postembryonically born neuron with rudimentary cilium.
AQR and its ciliated dendrite are directly exposed to the pseudocoelomic body fluid. AQR axonal process projects into the ring.
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-25; transmembrane receptor guanylate cyclase
- GCY-32; soluble guanylate cyclase
- GCY-34; soluble guanylate cyclase

- GCY-35; soluble guanylate cyclase, binds molecular oxygen and mediates oxygen sensation. Heterodimerizes with GCY-36
- GCY-36; soluble guanylate cyclase
- GCY-37; soluble guanylate cyclase
- NLP-37; neuropeptide-like ppetide
- NPR-1; receptor for flp-18- and flp-21-encoded peptides

(Wormbase; Altun, 2011; Gray et al., 2004; Coates and de Bono , 2002; Yu et al., 1997)
- Functions in aerotaxis, and along with PQR, 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) behaviors. 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) low-activity allele or that lack npr-1 function tend to dwell (slow down) on food in low ambient O2 and roam around or aggregate (at the borders of the food lawn) 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 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)

Click image for closeup view Click pictures for higher resolution images

Larval migration of of Q blast cells and their progeny (the progeny that die are indicated by an "x"):

Last revision: January 15, 2013