Term
| nociceptor firing pattern |
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Definition
| regular receptors fire up until certani limit, once stimulus hits that limit, receptor has plateaud and nociceptor starts firing. High threshold of activation, and slowly adapting. wanna make sure signal gets to the brain before it adapsts |
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Term
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Definition
| First pain, activated by A delta. Second pain, C fiber- is slower transission, and not quiteas high level of actiation. |
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Term
| local anasethetic blocking which elemnet, |
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Definition
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Term
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Definition
| Vanilloid receptor boindign and transient receptor (trpv 2 and Vr1). Channels in C fibers are activated by moderate heat and capsacin. Allows influx of sodium adn calcium into cells causin action potential. Capsascin as analgesic ,b ecause pplication will cause desensitazion. |
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Term
| Functional compoennets of pain |
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Definition
Sensory discirmiantive component: location, intensity and quality of stimulation. Pthways that target traditional somatosensory areas of cortex
affective motivvation componenet : unpleasant quality of the experience, acitvation of the autonomic (figt or flight ) reaction. Depends ona didtional cotical and brainstem patwhays. |
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Term
| anterolateral pahtways that transit nociceptive iformation |
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Definition
Spinothalamictract- discriminative aspectsof pain adn temperature
spinoreticular tract-emotional and arousal aspects of pain.
spionomesencephalic- Central modulation of pain. |
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Term
| midline thalamic nlcuei and itnralaminar nuclei |
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Definition
| recevei informaiton from spinoreticualr and spinomesencephalci tracts |
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Term
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Definition
| goes up in atnerolateral system but branceshes off to syanspe at reticular formation fo the pons and medulla |
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Term
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Definition
| branches of anterior alteral and goes to superior collicus and periqduectal gray of midbrain- there are descending pathways from this to modulate ifnormation. |
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Term
| intralaminar and mediorsal nuclei of thalamus |
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Definition
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Term
| regions activated by painful stimuli |
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Definition
| primarysomatosensory cortex, anteiror cingulate cortex, insular cortex |
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Term
| gray matter decreasedi n chornic pain |
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Definition
| the pain sensors are getting constantly actiated , excitotoxicity and start dying off |
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Term
| descending contorl pain perception |
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Definition
| stress induced analgesia. placebo effect = physiolocial resposne follwign adminsitariton fo pahrmacollogicaly inert remedy. effecs can be block by inhbiitro fo opiate recepors |
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Term
| descending systems pathway |
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Definition
| from dorsal hon up the anterolateral system goestosoamtic snesory cotex, which cuases descending dwn amygdala and hypothalamus gets to midbrain periaqueductal gray and then parbrachial nucleus, medullayr reticular formation, loc coeruleus, and raphe nucleus down to dorsal horn where they modulate C fibers and the nateroalteral systme |
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Term
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Definition
| from hypothalamus/amygdala to midbrain pperiaqueductal gray matter to raphe nucleus in rostral ventral medulla to dorsal horn wher synapses onto C fibersand ascending second order projection neurons |
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Term
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Definition
| locas ceruleus in rostral pons to dorsal horn. |
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Term
| descending control of nociceptive info at spinal cord level |
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Definition
| Thereare enkephalins and dynorphisn in periqueductal grya and psinal cord. and Endorphisn in hypothalamus which projectot periqudecutal gray. In this case there is a descending neuron (i.e. form raphe nuclei) which synanspe to enkephalin containg lcoal cirucitn euron- this sends signals to C fiber, inhibiting it and reducing activation fo dorsal horn projection neuron. |
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Term
| look at sumamr ysldieo fascending/descending pathways |
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Definition
Dorsal horn second order proejciton neurons , projectiosn to periaquedcutal gray ,peribrachial neucli, hypothalamus thalamus, amybgdala ,that will go to primary somatosensory cortex , from primaryu somatosensory cortex to parietal cortex, to secondary somatosensory cortex , to the anterior cingulated cortex and insula from the spinoreticular and spinomesencephalic pathway
The descneidng pathway come form anterior cingulated and insula down to the pariaqueductal gray and to rostroventromedulla, where the seratogenric and noerpinerphine neurosn are that go down to dorsal horn of the spinal cord. |
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Term
| acigation of descendign pain contorl systems can be cloked by anloxone |
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Definition
| peiopel giving palcebo showed decreased priamry sensory cortex actiaiton, and icnreased decending pathway activation. though naloxoen inhbiited these affects. |
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Term
| LEsion fo parietal lobe or primary snesory cortex |
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Definition
| contralateral nubm tingling or pain |
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Term
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Definition
| xontralateral burnign pain (dejerine roussy (thalamic sydnrome) |
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Term
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Definition
| tingling numb sensation, tight band lieksneastion aroudn trunk or limbs, fe ling ofhaving guze onf igners. ** electricity sensation down back and exterimtiesu pon neck flesion (lehrmittes sign) |
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Term
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Definition
| sharp, burnign o r searing pain |
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Term
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Definition
| radicular pain with numbness/tingilingi n dermatomal distrubtion |
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Term
| cuases of sensory enuropatheis |
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Definition
| diabetes - distal symetmrical polyenuropahty due to decrease in microvascualteure flwo to periphearal nerves. |
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Term
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Definition
| demyelination follwoign viral inefection resulting in parasthesias |
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Term
| mechanical sensory neuropathy |
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Definition
| neurapraxia wallerian degeneration casualgia neuralgia |
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Term
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Definition
| mild mechanical insult, tempeorary impairemtn of nerve conduction |
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Term
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Definition
| severe insult- degenration distal to site of injury but regen may occur |
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Term
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Definition
| incomplete regenration, burnignsenasation |
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Term
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Definition
| severe persistant pian in distrubtion fo crania lro spinal neve |
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Term
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Definition
| causes neuropathy: lowers threshold of DRG so almsot beign to fire spontaneously |
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Term
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Definition
| inability to xperience pain. Mutation prevents excitatory transmission in DRG neurons. Recessive Mutation channel results in no firing in resposne to stimulus. Good target for drugs because wont have side effects of anesthetic drugs |
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Term
| Inherited erythromelalgia/parxocysmal extreme pain |
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Definition
| drominant muations in souiducm channe lare increased function- resulting in increased pain sensation |
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Term
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Definition
| folowoign repeated aplciation of noxious stimuli, neightoring nociceptors that were nto rsponsive now becomce responsive . PRomotes heailing and prenetsi nfection. |
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Term
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Definition
| somethign that was normally painful before that will become more painful. |
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Term
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Definition
| induction fo pain that wasnt painful at all is painful now. |
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Term
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Definition
| when injury, ifnlammatory soup is released (atp prostaglandin bradyinin, histamine) - resutls ianxon reflex, decrease in threshold of acitvaiton fo aferent axon. sensitize the area. results in secretion neuropeptides (substance P and CGRP)- cause vasodilation of arterials nad increased BF. Substance P causes degranualtion fo mast cells resutlign more histamine release to cause even lower thereshold. affects DRG . NSAIDS- develoepd basedo nthese compoudns . Cox preents syntehsis of psrostaglandins |
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Term
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Definition
| Central sensization occurs iwthin dorsal horn – icnreasei ne xcitability fo dorsal horn enruosn that can be transcription idnepepndant or transcription depepndant , mechanism underlying allodyinia. Wind up – if you give same painful stimulus repeatedly, enhanced response of central projection enruo tn same stimulus each time you give it , last only during sitmualtion period. If get enough activation , get transcription of new genes, this is more lon g lasting change in activation of central projection enruons. This mechanism can also be activated and mediated by cox . IF you avhe cox2 inhibitors, those will act peripherally and centreally. |
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Term
| central sensiztaion mechanism |
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Definition
| Give stimulus indicated by arrows, stimulus is the saem each time, but the actiaviton fo the neuron incerasesd eachsubsequent delivery ofh te s timulus. Under acute pain u have release of glutamate one of major neuroransmitters. Glutamate gets released and binds to AMPA receptors , ,but cannot activate nMDA receptors yet because they have mangesiu m ion block. Udner hronic pain when have increased relase of neurotranmistetrs over prolonged period of time. You get activation of ampa receptors and enough enough glutamate is released that NDMA receptor block is released, which results in neuropeptides us cha s substance P and then expression fo genes changes. More lognlasting and semipermannetchange |
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Term
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Definition
| Activation nof lwo threshold mechanoreceptors modulates amout nfo pain s nesation. Normally have pain coming in through hc fiber or nociceptor , synapsing in dorsal horn onto second orderp oejciton neuron sending pain signal up the anterolateral system. By activating a mechanoreceptor via a beta fiber (that will go up dorsal columns), small branch goes to inhibitory interneuron of dorsal horn , when that interneuron is activated by a beta fiber , that will inhibit dorsal hor nprojectio nneruon. SO there will be les signal going up through anterolateral system, closing the gate to pain. C fibers activate dorsal horn projection neurons , but las o inhibit inhbitroy interneruons. Closing of gate to pain- activating inhibitory itnerneruon. Open gate to pain- ihibiting interneurons. TENS stimulation- activation of A beta fibers , closing gate to pain. |
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Term
| dorsal column pathway for viscreal pain |
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Definition
| Hwo do we sense visceral pain?- pain for the itnestines is sent hrough dorsal column pathway rather than STT sytem. Fi have afferent fiber coming inf rom itnestines It will synapse in intermediate gray zone and send second order proejciton neuron via dorsal coumn pathway up to nuclei acrossi tneracturefiberu p medial nlemniscus to thalamus and from thalamust o insular cortex. For visceral pain |
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Term
| midlien meylotomy for visceral pain |
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Definition
| Evidcence ofr this pathway- surgical itnerventiosn forvisceral pain midline myleotomy , severing axosn very closeot midline of spinal cord, light gray area is severed. Reduce amount of pain sensation I nveiscera. – severing dorsal column |
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Term
| cordotomy for cutaneous pain |
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Definition
| Cordtotomy for cutaneous pain- surgical intervention where lesioning lateral funiclulsu form the dentate ligament to the line of ventral rootelets, wil lahve to do it several segemtns rostaral or highest level of pain, it takes two seegemtns for those fibers to deccusate. Problem lies two segemtn rostral to pain sensation. |
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Term
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Definition
| Theres also the concept that visceral pain is conveyed centrally by neurons that carry cutaneous pain. STT pathway can also be used for visceral , but both project onto same second order neuron in the dorsal horn. Innervation from skin may come and project to this particular second order neuron and innerationfrom the intestine will rpeojct into the same second order neuron. So that hwen this neuron goes up to the thalamus and cortex, the thalamus and thecortex cannot discrimtinate where that pain originated form, whether form itnestiens or sk in. This leasd to referred pain. For ex if suffer form acid reflux, this will be refered to chest wall. Similiary, patients who have decreased bf to heart, have angina pain, have pain out ot upper chest wall and left arm. This isdue to commonality fo second relay neuron in pathway by both of these sysystems. |
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