The role of histamine H1, H2and H3receptors of ventral posteromedial nucleus of thalamus in modulation of trigeminal pain.
Histamine receptors are involved in supraspinal modulation of pain. In the present study, we investigated the effects of microinjection of histamine H1, H2and H3receptor antagonists and agonists into the ventral posteromedial (VPM) nucleus of the thalamus on two models of trigeminal pain. Right and left sides of VPM were implanted with two guide cannulas. Corneal pain was induced by local corneal surface application of hypertonic saline and the number of eye wipes was recorded. The duration of face rubbing, as an orofacial pain measure, was recorded after subcutaneous (s.c.) injection of capsaicin into the vibrissa pad. 2-pyridylethylamine (2-PEA, a histamine H1receptor agonist, 4µg/site) and dimaprit (a histamine H2receptor agonist, 1 and 4µg/site) suppressed corneal and orofacial pains. Mepyramine (a histamine H1receptor antagonist) and ranitidine (a histamine H2receptor antagonist) at the similar doses of 0.5, 2 and 8µg/site alone had no effects on trigeminal pain. Prior microinjection of mepyramine and ranitidine at a similar dose of 8µg/site inhibited the antinociceptive effects of 2-PEA (4µg/site) and dimaprit (4µg/site), respectively. Immepip (a histamine H3receptor agonist, 1 and 4µg/site) increased, and thioperamide (a histamine H3receptor antagonist, 2 and 8µg/site) attenuated nociceptive responses. Prior microinjection of thioperamide (8µg/site) prevented immepip (4µg/site)-induced nociception. These chemicals did not change locomotor behavior. It is concluded that post-synaptic histamine H2, and to a lesser extent H1, receptors and pre-synaptic histamine H3receptor may be involved in VPM modulation of trigeminal pain.
Division of Physiology, Department of Basic Sciences, Faculty of Veterinary Medicine, Urmia University, Urmia 5756151818, Iran. Electronic address: e_tamaddonfard@yahoo.com.
Esmaeal
E
Tamaddonfard
Division of Physiology, Department of Basic Sciences, Faculty of Veterinary Medicine, Urmia University, Urmia 5756151818, Iran.
Amir
A
Erfanparast
Division of Physiology, Department of Basic Sciences, Faculty of Veterinary Medicine, Urmia University, Urmia 5756151818, Iran.
Hamid
H
Ghasemi
Division of Physiology, Department of Basic Sciences, Faculty of Veterinary Medicine, Urmia University, Urmia 5756151818, Iran.
Farzin
F
Henareh-Chareh
Drug Logistics Manager of Health Deputy, Urmia University of Medical Sciences, Urmia, Iran.
Mansoor
M
Hadidi
Division of Pathology, Department of Pathobiology, Faculty of Veterinary Medicine, Urmia University, Urmia 5756151818, Iran.
Navideh
N
Mirzakhani
Division of Physiology, Department of Basic Sciences, Faculty of Veterinary Medicine, Urmia University, Urmia 5756151818, Iran.
Sahar
S
Seyedin
Division of Physiology, Department of Basic Sciences, Faculty of Veterinary Medicine, Urmia University, Urmia 5756151818, Iran.
Mina
M
Taati
Division of Physiology, Department of Basic Sciences, Faculty of Veterinary Medicine, Urmia University, Urmia 5756151818, Iran.
Reza
R
Salighedar
Division of Physiology, Department of Basic Sciences, Faculty of Veterinary Medicine, Urmia University, Urmia 5756151818, Iran.
Sara
S
Salimi
Division of Physiology, Department of Basic Sciences, Faculty of Veterinary Medicine, Urmia University, Urmia 5756151818, Iran.
Farshad
F
Safaei
D000818:Animals; D005157:Facial Pain / Q000378:metabolism* / Q000503:physiopathology; D008297:Male; D051381:Rats; D017208:Rats, Wistar; D011968:Receptors, Histamine / Q000378:metabolism*; D011969:Receptors, Histamine H1 / Q000378:metabolism; D011970:Receptors, Histamine H2 / Q000378:metabolism; D018100:Receptors, Histamine H3 / Q000378:metabolism; D014276:Trigeminal Nerve / Q000378:metabolism / Q000503:physiopathology; D020651:Ventral Thalamic Nuclei / Q000378:metabolism*
D011968:Receptors, Histamine; D011969:Receptors, Histamine H1; D011970:Receptors, Histamine H2; D018100:Receptors, Histamine H3
Histamine receptors; Rats; Trigeminal pain; Ventral posteromedial nucleus; capsaicin (PubChem CID: 1548943); dimaprit dihydrochloride (PubChem CID: 90045); dimethyl sulfoxide (PubChem CID: 679); distilled water (PubChem CID: 962); ethanol (PubChem CID: 702); immepip (PubChem CID: 3035842); mepyramine maleate (PubChem CID: 5284451); normal saline (PubChem CID: 5234); ranitidine hydrochloride (PubChem CID: 3033332); thioperamide maleate (PubChem CID: 3035905)