Characterisation of monoamine G-protein coupled receptors in Octopus vulgaris

Octopuses are an emerging model organism in neurobiology due to their unique nervous system and capacity for intelligence. However, due to this novelty, nothing is currently known about many of their receptors, including those involved in neuromodulation. Given the historical significance of dopamine action in the brain and our recent findings implicating it as one of the three main neurotransmitters used in the optic lobe, we have chosen to explore dopaminergic GPCRs in Octopus vulgaris. We have identified approximately twenty candidate octopus monoamine GPCRs, utilising protein sequence similarity network analysis and phylogenetics, and are using electrophysiology to characterise their ligands in Xenopus oocytes. A single-cell RNA sequencing dataset of the paralarval octopus brain is being applied to identify potential spatial associations between these GPCRs and the optic system. Fluorescent in situ hybridisation will then be executed to identify exact layers where these GPCRs are expressed. We have successfully characterised the first octopus dopaminergic GPCR and RNA seq indicates it is expressed in neurons in the central brain. This process will be continued and will allow us to generate a more complete hypothesis regarding the integration of dopamine receptors with other neurotransmission, especially relating to its use in processing visual information.