Hi. This is Christoph Stein from Berlin, Germany and I was asked to talk about G-protein-coupled receptors and pain.
Pain is the processing of sensory information and integrated in the brain. So when you look at this slide all the way on top, this is where the person perceives pain as an integrated response of many different stimuli that start in the periphery and end up in the central nervous system. So now look at peripheral ending of the sensory neuron, all the way at the bottom of this slide, there are many many different stimuli that can initiate this nociceptive process. So at this stage, we talk about nociception which is the beginning of the signal that ends up in the brain. You can see cytokines, you can see proteases, bradykinin, keratinocytes, many different types of physical stimuli, mechanical, heat, cold and chemical stimuli. All of these excite nociceptive neurons at the peripheral ending. Thereafter, there is an action potential that is transmitted by the primary afferent neuron towards the spinal cord where it is transmitted via synaptic processes and then gets transferred upwards to the central nervous system.