Tacr1, also known as the neurokinin 1 receptor, is a G-protein-coupled receptor. It binds to substance P, a neuropeptide, and is involved in multiple biological pathways. It plays a crucial role in neural circuits related to sexual behavior, pain, and metastasis, and is also associated with alcohol dependence, postoperative nausea and vomiting, and neurovascular coupling [1-9].

In male sexual behavior, Tacr1-expressing neurons in the POA (innervated by BNSTprTac1 neurons) are essential. Activation of POATacr1 neurons can trigger mating even in satiated males and is rewarding [1]. In breast cancer, neuronal substance P acts on tumoral Tacr1 to drive metastasis through a non-canonical pathway [2]. In pain-related studies, Tacr1-expressing neurons form parallel ascending circuits conveying cutaneous signals. Activation of spinal Tacr1-expressing neurons can evoke pain-related behaviors, and PBN-SLTacr1 neurons play a role in ongoing pain sensation [3,4].

In conclusion, Tacr1 is involved in diverse biological processes. Mouse models with Tacr1-related manipulations have revealed its significance in male sexual behavior, cancer metastasis, and pain perception. These findings contribute to understanding the underlying mechanisms of these biological processes and related diseases, potentially guiding the development of targeted therapies.