title: Time course analysis of the effects of botulinum neurotoxin type A on pain and vasomotor responses evoked by glutamate injection into human temporalis muscles.
abstract: The effect of botulinum neurotoxin type A (BoNTA) on glutamate-evoked temporalis muscle pain and vasomotor responses was investigated in healthy men and women over a 60 day time course. Subjects participated in a pre-BoNTA session where their responses to injection of glutamate (1 M, 0.2 mL) and saline (0.2 mL) into the temporalis muscles were assessed. On Day 1, BoNTA (5 U) was injected into one temporalis muscle and saline into the contralateral temporalis muscle, in a randomized order. Subjects then received intramuscular injections of glutamate (1 M, 0.2 mL) into the left and right temporalis muscles at 3 h and subsequently 7, 30 and 60 days post-injection of BoNTA. Pain intensity, pain area, and neurogenic inflammation (skin temperature and skin blood perfusion) were recorded. Prior to BoNTA treatment, glutamate evoked significantly greater pain and vasomotor reactions (P < 0.001) than saline. BoNTA significantly reduced glutamate-evoked pain intensity (P < 0.05), pain area (P < 0.01), skin blood perfusion (P < 0.05), and skin temperature (P < 0.001). The inhibitory effect of BoNTA was present at 3 h after injection, peaked after 7 days and returned to baseline by 60 days. Findings from the present study demonstrated a rapid action of BoNTA on glutamate-evoked pain and neurogenic inflammation, which is in line with animal studies.
authors: Center for Sensory-Motor Interaction (SMI), Department of Health Science and Technology, Aalborg University, Aalborg DK-9220, Denmark. larissa@hst.aau.dk.
authors: Larissa Bittencourt
authors: LB
authors: da Silva
authors: Center for Sensory-Motor Interaction (SMI), Department of Health Science and Technology, Aalborg University, Aalborg DK-9220, Denmark. demil07@student.aau.dk.
authors: Dolarose
authors: D
authors: Kulas
authors: Neurology Department, Aalborg University Hospital, Aalborg DK-9100, Denmark. ali.karshenas@rn.dk.
authors: Ali
authors: A
authors: Karshenas
authors: Center for Sensory-Motor Interaction (SMI), Department of Health Science and Technology, Aalborg University, Aalborg DK-9220, Denmark. brcairns@mail.ubc.ca.
authors: Brian E
authors: BE
authors: Cairns
authors: Neurology Department, Aalborg University Hospital, Aalborg DK-9100, Denmark. fwb@rn.dk.
authors: Flemming W
authors: FW
authors: Bach
authors: Center for Sensory-Motor Interaction (SMI), Department of Health Science and Technology, Aalborg University, Aalborg DK-9220, Denmark. lan@hst.aau.dk.
authors: Lars
authors: L
authors: Arendt-Nielsen
authors: Center for Sensory-Motor Interaction (SMI), Department of Health Science and Technology, Aalborg University, Aalborg DK-9220, Denmark. gazerani@hst.aau.dk.
authors: Parisa
authors: P
authors: Gazerani
mesh_terms: D000328:Adult; D000700:Analgesics / Q000494:pharmacology / Q000627:therapeutic use*; D019274:Botulinum Toxins, Type A / Q000494:pharmacology / Q000627:therapeutic use*; D004311:Double-Blind Method; D005260:Female; D018698:Glutamic Acid; D006801:Humans; D007273:Injections, Intramuscular; D008297:Male; D018482:Muscle, Skeletal / Q000098:blood supply / Q000187:drug effects* / Q000502:physiology; D063806:Myalgia / Q000139:chemically induced / Q000188:drug therapy* / Q000503:physiopathology; D012039:Regional Blood Flow / Q000187:drug effects; D012727:Sex Characteristics; D012881:Skin Temperature / Q000187:drug effects; D055815:Young Adult
chemical_list: D000700:Analgesics; D018698:Glutamic Acid; D019274:Botulinum Toxins, Type A