The cell biology of acute itch

Abstract

Itch, the irritation we feel and the relief that comes from scratching, is an evolutionary warning system and defense against harmful environmental agents. Although once considered a subtype of pain, itch is now recognized as a unique sense, with its own distinct physiology and cell receptors. Here, we discuss recent advances in our understanding of itch and the molecular players that mediate this sensory modality.

Functional magnetic resonance imaging in dermatology: The skin, the brain and the invisible

“…[73,74] The peripheral pathophysiology of itch is highly complex and cannot be adequately covered here; however, the following references provide a comprehensive overview. [55,[74][75][76][77] In the reviewed fMRI studies, numerous cutaneous itch models perceived itch qualities and response to antipruritic treatments. [75,78,79] C-fibres transmit itch signals to secondary neurons in the dorsal horn, from where they ascend in the contralateral spinothalamic tract to the thalamus, which distributes the signals to the itch-processing brain structures.…”

Nerve reinnervation and itch behavior in a rat burn wound model

“…After the acute phase, a burn wound will start healing and new tissue will be formed. In this phase, wound healing is often associated with itch, usually described as an unpleasant sensation in the skin that elicits the desire to scratch . Complaints commonly start within one month postburn, with a peak at six months .…”

“…This shows not only the need for finding additional treatment modalities for itch in burn patients but also for increased knowledge about the processing of itch in the central nervous system, which is still incomplete. It has been shown recently that transmitters, like natriuretic polypeptide B (NPPB) and gastrin releasing peptide (GRP) and their receptors, are specifically involved in itch rather than in pain transmission . However, most sensory neurons in the spinal cord and brainstem that respond to itch are also sensitive to nociceptive stimuli, suggesting that a pathway dedicated exclusively to itch may not exist .…”

Peripheral and spinal 5-HT receptors participate in cholestatic itch and antinociception induced by bile duct ligation in rats

“…Acute itch serves as a self-protective mechanism against potential harmful environmental irritants or parasites2. However, chronic itch is a debilitating symptom that arises from many systemic disorders, such as dermatologic diseases (e.g.…”

“…Antihistamines are often clinically prescribed for treating allergy itch; however, they are inefficient for many aforementioned chronic itch conditions4. Although the recent discovery for itch-specific neural pathway678, novel itch mediators and receptors9101112, greatly improves our understanding on acute itch2, the pathogenesis of chronic itch associated with systemic disorders remains enigmatic.…”