Calcium Imaging in Olfaction: Non-rodent Mammalian Species

The mammalian olfactory system plays a crucial role in detecting and transducing a diverse array of molecular cues present in the environment influencing in the display of behaviors such as feeding, reproductive function, and avoidance of predators. The recognition of these chemical signals primarily involves activation of olfactory and vomeronasal sensory neurons located in the main olfactory epithelium and the vomeronasal organ, respectively. Calcium imaging is a well-established method in rodents and insects to evaluate sensory cell activity, although its utilization in other species, particularly large mammals, is less prevalent. Here, we describe recent methodological advances using calcium imaging to scrutinize the response patterns of olfactory and vomeronasal sensory neurons isolated from goats and pigs, with potential applications in other species as well. Our approach reports cell responses to olfactory stimuli and provides a method for molecular characterization of the activated cells through immunolabeling. This methodology enables us to analyze the response patterns of single sensory cells aligning them with specific molecular profiles, providing a valuable tool for identifying mammalian chemosignals and their respective receptors.