The serotonergic raphe magnus (RMg) and dorsal raphe (DR) nuclei are crucial pain-regulating structures, which nociceptive activity is shown to be altered in gut pathology, but the underlying neuroplastic changes remain unclear. Considering the importance of 5-HT1A receptors in modulating both pain and raphe neuronal activity, in this study, we aimed to determine whether 5-HT1A-dependent visceral and somatic nociceptive processing within the RMg and DR is modified in postcolitis conditions. In anaesthetised male Wistar rats, healthy control and recovered from TNBS-induced colitis, the microelectrode recordings of RMg and DR neuron responses to noxious colorectal distension (CRD) or tail squeezing (TS) were performed prior and after intravenous administration of 5-HT1A agonist, buspirone.
View Article and Find Full Text PDFTranscranial Doppler ultrasonography is used to study intracranial blood flow changes associated with migraine in humans, but whether this method is helpful in preclinical settings is yet unknown. To identify changes in rat intracranial blood flow specific to trigeminovascular activation-a key process in migraine pathophysiology-we measured Doppler indices in the middle cerebral artery and basilar artery before, during, and after dural or somatosensory electrical stimulation. Hemodynamic changes specific to dural stimulation were tested further in separate experiments.
View Article and Find Full Text PDFThe midbrain periaqueductal gray (PAG) is a key structure involved in the supraspinal modulation of pain. Previous studies have reported the association of gut inflammation-triggered chronic abdominal pain with structural and neuronal alterations within the PAG. However, whether PAG-executed visceral nociception processing and descending modulation are altered in gut pathology is not known.
View Article and Find Full Text PDFMigraine is associated with the activation and sensitisation of the trigeminovascular system and is often accompanied by mechanical hyperalgesia and allodynia. The mechanisms of mechanotransduction during a migraine attack are yet unknown. We have proposed that the ion channel Piezo1 may be involved, since it is expressed in endothelial cells as well as in trigeminal ganglion neurons, and thus, may contribute to the activation of both the vascular and neuronal component of the trigeminovascular system.
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