Anatomy, physiology and pharmacology of pain

Pain is a complex perceptual experience. The transmission of pain involves both peripheral and central processes and can be modulated at many levels. Peripheral sensitization causes increased afferent input to the spinal cord. Numerous receptors and ion channels are involved. Pain can induce physiological and anatomical changes within the nervous system which are implicated in the development of neuropathic and visceral pain states. The complexity of pain transmission means there are many pharmacological targets and multimodal therapy is required to optimize pain control.