Name: pain signaling and inflammation
Uploaded: 2025-10-23T11:49:14.000Z
Duration: 1 min 44 s
Channel: JoVE

- [Verteller] Nociceptie, meestal pijn genoemd, is het proces waardoor een schadelijke stimulans wordt overgedragen door het perifere en centrale zenuwstelsel om te waarschuwen voor mogelijk letsel of letsel. Wanneer een schadelijk signaal wordt gedetecteerd, worden nociceptoren, vrije zenuwuiteinden, geactiveerd. Nabijgelegen mestcellen geven chemicaliën af, zoals histamine, terwijl macrofagen cytokines uitscheiden, kleine eiwitten die kritische factoren zijn in de immuunsignalering.

Tegelijkertijd geven de axonen van de nociceptoren het signaal door naar de rughoorn van het ruggenmerg, voornamelijk via twee verschillende pijn vezels. De eersten die moeten worden geactiveerd zijn de dun myelineerde A-Delta-vezels, die onmiddellijk scherpe en goed gelokaliseerde pijn op een zeer hoge snelheid uitvoeren, om het lichaam in staat te stellen zich terug te trekken van de schadelijke prikkel. Het andere type axonen zijn C-vezels, die langzaam geleiden omdat ze niet gemyelineerd zijn en een langdurige brandende pijn overbrengen.

Vanuit het ruggenmerg steken de pijnsignalen over en bewegen zich naar de hersenstam, gevolgd door de thalamus en somatosensorische cortex, waar de pijnsignalen worden geïnterpreteerd om de locatie van het letsel te bepalen. Extra hersengebieden verwerken de pijn, met name corticolimbische structuren, waaronder de amygdala en de prefrontale cortex, die betrekking hebben op emotionele herinneringen en cognitie. Uiteindelijk dragen de meervoudige interacties in de hersenen bij aan de subjectieve perceptie die individuen ervaren.

nociceptie

Nociception

Nociceptie – het vermogen om pijn te voelen – is essentieel voor de overleving en het algehele welzijn van een organisme. Schadelijke stimuli zoals stekende pijn van een scherp voorwerp, hitte van een open vlam of contact met bijtende chemicaliën worden eerst gedetecteerd door sensorische receptoren, nociceptoren genaamd, die zich op de zenuwuiteinden bevinden. Nociceptoren brengen ionkanalen tot expressie die schadelijke stimuli omzetten in elektrische signalen. Wanneer deze signalen via sensorische neuronen de hersenen bereiken, worden ze als pijn ervaren. Pijn helpt het organisme dus om schadelijke prikkels te vermijden.

Het immuunsysteem speelt een essentiële rol bij pijnpathologie. Bij het tegenkomen van schadelijke stimuli geven immuuncellen zoals mestcellen en macrofagen die aanwezig zijn op de plaats van het letsel ontstekingschemicaliën af, zoals cytokinen, chemokinen, histaminen en prostaglandinen. Deze chemicaliën trekken andere immuuncellen zoals monocyten en T-cellen naar de plaats van de verwonding. Ze stimuleren ook nociceptoren, wat resulteert in hyperalgesie – een intensere reactie op een eerder pijnlijke stimulus, of allodynie – een pijnlijke reactie op een normaal onschadelijke stimulus zoals een lichte aanraking. Een dergelijke pijnsensibilisatie helpt de gewonde plek tijdens genezing te beschermen.

In sommige gevallen overleeft pijn zijn rol als acuut waarschuwingssysteem als de sensibilisatie na verloop van tijd niet verdwijnt. Chronische pijn – aanhoudende of terugkerende pijn die langer dan drie maanden aanhoudt – gaat vaak gepaard met ontstekingsaandoeningen zoals reumatoïde artritis. Niet-steroïde anti-inflammatoire geneesmiddelen (NSAID's) zoals aspirine en ibuprofen verminderen de pijn door de synthese van de ontstekingsmoleculen prostaglandinen te remmen. NSAID's en opioïden die momenteel worden gebruikt om pijn te bestrijden, hebben echter te kampen met ernstige bijwerkingen en kans op verslaving. Daarom kan het begrijpen van de mechanismen die ten grondslag liggen aan pijnpathologie helpen effectievere medicijnen te ontwikkelen om de pijnperceptie te onderdrukken met minder ernstige negatieve bijwerkingen.

Nociceptie

Nociception&#8212;the ability to feel pain&#8212;is essential for an organism&#8217;s survival and overall well-being. Noxious stimuli such as piercing ...

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pain signaling and inflammation

Pain signaling begins when the body detects a harmful stimulus. Sharp objects, open flames, and corrosive chemicals can trigger this response. Sensory receptors called nociceptors, which sit on nerve endings, detect these noxious stimuli and use ion channels to turn them into electrical signals.

Those electrical signals travel through sensory neurons to the brain, where they are experienced as pain. This warning system helps an organism avoid damage and stay safe. Pain is therefore an important part of survival and overall well-being.

The immune system also shapes pain after an injury. Mast cells and macrophages at the injury site release inflammatory chemicals such as cytokines, chemokines, histamines, and prostaglandins. These signals attract more immune cells, including monocytes and T cells, and they also stimulate nociceptors.

This immune response can increase pain sensitivity. Hyperalgesia is a stronger response to a stimulus that was already painful. Allodynia is pain caused by something that is usually not painful, such as light touch. These changes help protect the injured area during healing.

Pain can become a problem when sensitization does not fade. Chronic pain is persistent or recurring pain that lasts longer than three months. It often occurs with inflammatory diseases such as rheumatoid arthritis. NSAIDs, including aspirin and ibuprofen, reduce pain by blocking the production of prostaglandins. However, NSAIDs and opioids can cause serious side effects and may lead to addiction, so researchers continue to study pain mechanisms to find safer drugs.

Pain Signaling and Inflammation

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classification of skeletal muscle fibers

Skeletal Muscle Fiber Speed and Energy

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cross-bridge cycle

Calcium Control in Muscle Contraction

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motor units

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The spinal cord is the main nerve pathway of the central nervous system. It carries sensory signals from the body to the brain and motor signals from the brain to the body. It begins at the foramen magnum, the opening at the base of the skull, and extends to the level of the first or second lumbar vertebra. In cross-section, the spinal cord is cylindrical and contains both gray matter and white matter. The central canal lies in the middle and is a remnant of the lumen of the primitive neural...

nociception

Pain signaling begins when the body detects a harmful stimulus. Sharp objects, open flames, and corrosive chemicals can trigger this response. Sensory receptors called nociceptors, which sit on nerve endings, detect these noxious stimuli and use ion channels to turn them into electrical signals. Those electrical signals travel through sensory neurons to the brain, where they are experienced as pain. This warning system helps an organism avoid damage and stay safe. Pain is therefore an...

key terms and concepts

Learn how nociceptors detect harmful stimuli, how inflammation boosts pain sensitivity, and why chronic pain can persist after injury.

Pain Signaling and Inflammation | JoVE K12

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Pain Signaling and Inflammation

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