Physiology of Pain

TOPICS COVERED IN THIS CHAPTER Peripheral pain mechanisms Primary afferent nociceptors Visceral afferents Sympathetic nervous system Peripheral sensitisation/inflammation Role of nerve growth factor in peripheral sensitisation Silent nociceptors Peripheral nerve injury Clinical implications for peripheral analgesic action Dorsal horn mechanisms Termination sites of primary afferents Outputs from primary afferents Neurotransmitters and neuromodulators Excitatory nociceptor transmission Peptides Intracellular events Spinal mechanisms following nerve injury and inflammation Central sensitisation and synaptic plasticity Sensory and physiologic changes Sprouting Modulation at a spinal level The gate theory γ-aminobutyric acid and glycine Clinical implications for modulation of spinal sensitisation Ascending spinal tracts Target structures Clinical implications Supraspinal structures Thalamus Cortical structures Descending modulation Brain structures involved in descending inhibition Neurotransmitter mechanisms Clinical implications Clinical significance of inflammation and nerve injury Pre-emptive analgesia Chronic pain Peripheral nerve blockade in chronic pain Transitions from acute to chronic pain