Effect of oxytocin and L-368,899 on the evoked meningeal nociception recorded at the trigeminocervical complex
SUMMARY: Migraine is a common, disabling, neurovascular disorder and its pathophysiology involves abnormal activation of trigeminocervical complex (TCC) neurons. METHODS: We performed in vivo electrophysiology in sevoflurane, anesthetized male Wistar (290-320g) rats. Under these conditions a craniotomy to expose the middle meningeal artery (MMA) region was made and unitary extracellular recordings of wide dynamic range neurons (WDRn) of TCC were performed. The nociceptive neuronal responses were evoked by dural electrical stimulation (20 electrical pulses at 0.5 Hz with 1-msec pulse duration at 0.1-3mA) to evoke the neuronal nociceptive response of TCC neurons. In these experiments, the WDRn recorded has convergence from dural tissue and the supraorbital area. The evoked neuronal activity was recorded, amplified, digitalized, and discriminated using CED hardware and Spike2 v5.15 software. The evoked nociceptive activity was analyzed with peri-stimulus time histograms (PSTH) that allowed to characterize the WDRn activity by their response latency: Aδ-fibers (3-33 msec) and C-fibers (26-80 msec). The role of OTR in the OXT (20 nmol) effect was tested using a highly selective and potent antagonist, the L-368,899 (20 nmol). KEY RESULTS: OXT inhibits the meningeal nociceptive neuronal activity in the TCC. The antinociceptive effect of OXT was abolished by pretreatment with the OTR antagonist. DATA CONTAINED IN THE .XLSX FILES. The .xlsx files contain the semi-processed raw data obtained in the electrophysiological experiments. All data were analyzed using the Spike 2 software to construct PSTH, the data generated were exported to .xlsx files. The file "1 - Control Group.xlsx" contains the data separated in several sheets for each cell recorded in the control group. The file "2 - OXT Group.xlsx" contains the data separated in several sheets for each cell recorded in the group of cells treated with OXT (20 nmol given in the trigeminocervical complex o TCC). The file "3- L3 + OXT Group.xlsx" contains the data separated in several sheets for each cell recorded in the group of cells pretreated with the OXT antagonist, the L-368,899 and OXT (20 nmol given in the trigeminocervical complex o TCC). In all files, the first sheet contains a summary of the content in this file.