Characterizing a new tool to manipulate area postrema GLP1R+ neurons across species.

Nausea is an uncomfortable sensation that accompanies many therapeutics, especially diabetes treatments involving glucagon-like peptide-1 receptor (GLP1R) agonists. Recent studies in mice have revealed that GLP1R-expressing neurons in the area postrema play critical roles in nausea. Here, we characterized a ligand-conjugated saporin that can efficiently ablate GLP1R+ cells from humans, mice, and the Suncus murinus, a small animal model capable of emesis. This new tool provides a strategy to manipulate specific neural pathways in the area postrema in the Suncus murinus and may help elucidate roles of area postrema GLP1R+ neurons in emesis during therapeutics involving GLP1R agonists.

Lys49 myotoxin from the Brazilian lancehead pit viper elicits pain through regulated ATP release.

Pain-producing animal venoms contain evolutionarily honed toxins that can be exploited to study and manipulate somatosensory and nociceptive signaling pathways. From a functional screen, we have identified a secreted phospholipase A2 (sPLA2)-like protein, BomoTx, from the Brazilian lancehead pit viper (Bothrops moojeni). BomoTx is closely related to a group of Lys49 myotoxins that have been shown to promote ATP release from myotubes through an unknown mechanism. Here we show that BomoTx excites a cohort of sensory neurons via ATP release and consequent activation of P2X2 and/or P2X3 purinergic receptors. We provide pharmacological and electrophysiological evidence to support pannexin hemichannels as downstream mediators of toxin-evoked ATP release. At the behavioral level, BomoTx elicits nonneurogenic inflammatory pain, thermal hyperalgesia, and mechanical allodynia, of which the latter is completely dependent on purinergic signaling. Thus, we reveal a role of regulated endogenous nucleotide release in nociception and provide a detailed mechanism of a pain-inducing Lys49 myotoxin from Bothrops species, which are responsible for the majority of snake-related deaths and injuries in Latin America.