''Nociceptors are the principal receptive sites that turn a noxious (injurious) environmental stimulus into an electric signal. They detect potentially harmful stimuli in the body, such as tissue damage, temperature extremes, and chemical or mechanical insults. They are located in the skin, joints, deep tissues, cornea, and dorsal root ganglia (DRG) or trigeminal ganglia (TG). When activated by noxious stimuli, nociceptors transmit information to the central nervous system (CNS) through the spinal cord dorsal horn or the nucleus caudalis. The information then travels to the brainstem and eventually the cerebral cortex, where pain is experienced. Studies suggest that substance P (SP) levels increase in the central nervous system (CNS) during depression and in response to psychological stress.''

ChatGpt