[Verse 1] Burned fingertip, thermoreceptors scream awake Nociceptors fire, transduction's what it takes A delta fibers sprint — sharp, precise, immediate pain C fibers crawl behind like a slow, sulfurous rain Dorsal horn receives 'em, glutamate drops its key Substance P unlocks the gate, signals running free Spinothalamic tract ascending, crossing to the other side Thalamus routes the signal, cortex where it's verified Anterior cingulate screaming "this is suffering, feel it" Somatosensory cortex maps the wound and seals it Then descending modulation — PAG sends orders down Serotonin, norepinephrine, dampen every sound Opioid interneurons gate the dorsal horn transmission That's the whole trajectory — nociception to remission [Chorus] Nociceptive — tissue damage, inflammation's game Neuropathic — nerve dysfunction, aberrant signals trained Nociplastic — no clear lesion but the CNS is changed NMDA, ketamine, sensitization named A-delta sprints, C-fibers stroll, thalamus routes the frame Trace the signal, name the pain, treat it with your brain [Verse 2] Patient one: post-herpetic, burning like a branding coal Allodynia from a bedsheet — that's a neuropathic toll The nerve itself is damaged, ectopic discharge lit Voltage-gated sodium channels misfiring every split First-line options — gabapentinoids to calm the flux Or tricyclics blocking reuptake, norepinephrine crux SNRIs also valid, duloxetine's your call For neuropathic — modulate the nerve signal at the wall Patient two: fibromyalgia, no tissue breakdown found Widespread hypersensitivity, pain without a wound Nociplastic presentation — central processing gone awry SNRIs and duloxetine still anchor your reply Milnacipran's another tool, pregabalin fits the case NSAIDs and opioids? They barely hold a place [Chorus] Nociceptive — tissue damage, inflammation's game Neuropathic — nerve dysfunction, aberrant signals trained Nociplastic — no clear lesion but the CNS is changed NMDA, ketamine, sensitization named A-delta sprints, C-fibers stroll, thalamus routes the frame Trace the signal, name the pain, treat it with your brain [Bridge] Now let me introduce the receptor that refuses to hush NMDA — voltage-gated, magnesium blocks the rush Repetitive C-fiber firing pulls that magnesium plug Calcium pours in ferociously, that's the central thug Wind-up phenomenon — every signal amplified PKC and CaMKII get phosphorylated wide Long-term potentiation in the dorsal horn, entrenched That's central sensitization — the efferent signal drenched Ketamine — an antagonist, plugs the channel cold Sub-anesthetic dosing interrupts the sensitized threshold For chronic pain refractory, perioperative care Ketamine's the scalpel cutting hyperalgesia bare The word *hyperekplexia* lives adjacent — exaggerated startle Central sensitization's cousin, both a neural snarl
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