title: Effects of the mas-related gene (Mrg) C receptor agonist BAM6-22 on nociceptive reflex activity in naive, monoarthritic and mononeuropathic rats after intraplantar and intrathecal administration.
abstract: MrgC receptors are selectively expressed on peripheral and central terminals of small calibre nociceptive fibres. Peptide agonists of the MrgC receptor were reported to modulate nociceptive transmission exerting either pro- or antinociceptive effects depending on site of action and pain model used. Here, we investigated the effect of intraplantar and intrathecal administration of the selective MrgC receptor agonist BAM6-22 on mechanically and electrically evoked nociceptive reflex activity as a uniform readout measure in naïve, monoarthritic and mononeuropathic rats. In naïve rats, intraplantar BAM6-22 enhanced, whereas intrathecal BAM6-22 did not modulate mechanically-evoked nociceptive reflex activity. In monoarthritic rats, intraplantar BAM6-22 had no effect, whereas intrathecal BAM6-22 inhibited mechanically evoked nociceptive reflex activity. In mononeuropathic rats, BAM6-22 reduced mechanically evoked nociceptive reflex activity after both intraplantar and intrathecal administration. BAM6-22 did not modulate electrically evoked nociceptive reflex activity in any condition. Thus, the results of the present investigation confirm and add to previous studies demonstrating that site of action, (patho)-physiological state and stimulus modality determine the effect quality of MrgC receptor agonists. It still needs to be explored how concurrent activation of peripheral and spinal MrgC receptors modulates nociceptive processing under conditions of both acute and chronic pain to evaluate the therapeutic potential of putative small molecule MrgC receptor agonists as innovative analgesics.
authors.affiliation: Grünenthal Innovation, Translational Science and Strategy, Pharmacology and Biomarker Development, Grünenthal GmbH, Zieglerstrasse 6, 52078 Aachen, Germany. Electronic address: wolfgang.schroeder@grunenthal.com.
authors.forename: Wolfgang
authors.initials: W
authors.lastname: Schröder
authors.affiliation: Dept. Biology Systems, Unit of Physiology, Faculty of Medicine, Universidad de Alcala, Campus Universitario, 28871 Alcala de Henares, Spain.
authors.forename: Matilde
authors.initials: M
authors.lastname: Alique
authors.affiliation: Dept. Biology Systems, Unit of Physiology, Faculty of Medicine, Universidad de Alcala, Campus Universitario, 28871 Alcala de Henares, Spain.
authors.forename: Juan Fernando
authors.initials: JF
authors.lastname: Herrero
mesh_terms: D000818:Animals; D001168:Arthritis / Q000150:complications / Q000503:physiopathology*; D004745:Enkephalins / Q000008:administration & dosage* / Q000494:pharmacology*; D007278:Injections, Spinal; D008297:Male; D009437:Neuralgia / Q000503:physiopathology*; D059225:Nociception / Q000187:drug effects* / Q000502:physiology*; D010446:Peptide Fragments / Q000008:administration & dosage* / Q000494:pharmacology*; D051381:Rats; D017208:Rats, Wistar; D043562:Receptors, G-Protein-Coupled / Q000819:agonists*; D012018:Reflex / Q000187:drug effects*
chemical_list: C000611533:BAM6-22 peptide; D004745:Enkephalins; C000591603:Mrgprc protein, rat; D010446:Peptide Fragments; D043562:Receptors, G-Protein-Coupled
keywords: Acute pain; BAM6-22; Chronic pain; MrgC receptor; Nociceptive reflex