title: Posterior hypothalamic modulation of light-evoked trigeminal neural activity and lacrimation.
abstract: Enhanced light sensitivity is a common feature of many neuro-ophthalmic conditions and some chronic headaches. Previously we reported that the bright light-evoked increases in trigeminal brainstem neural activity and lacrimation depended on a neurovascular link within the eye (Okamoto et al., 2012). However, the supraspinal pathways necessary for these light-evoked responses are not well defined. To assess the contribution of the posterior hypothalamic area (PH), a brain region closely associated with control of autonomic outflow, we injected bicuculline methiodide (BMI), a GABAa receptor antagonist, into the PH and determined its effect on the encoding properties of ocular neurons at the ventrolateral trigeminal interpolaris/caudalis transition (Vi/Vc) and caudalis/upper cervical cord junction (Vc/C1) regions and on reflex lacrimation in male rats under isoflurane anesthesia. BMI markedly reduced light-evoked (>80%) responses of Vi/Vc and Vc/C1 neurons at 10 min with partial recovery by 50 min after injection. BMI also reduced (>35%) the convergent cutaneous receptive field area of Vi/Vc and Vc/C1 ocular neurons indicating that both intra-ocular and periorbital cutaneous inputs were affected by changes in PH outflow. Light-evoked lacrimation was reduced by >35% at 10 min after BMI, while resting mean arterial pressure increased promptly and remained elevated (>20 mmHg) throughout the 50-min post-injection period. These results suggested that PH stimulation, acting in part through increased sympathetic activity, significantly inhibited light- and facial skin-evoked activity of ocular neurons at the Vi/Vc and Vc/C1 region. These data provide further support for the hypothesis that autonomic outflow plays a critical role in mediating light-evoked trigeminal brainstem neural activity and reflex lacrimation.
authors: Department of Diagnostic and Biological Sciences, University of Minnesota School of Dentistry, Moos Tower 18-186, 515 Delaware Street SE, Minneapolis, MN 55455, USA.
authors: A
authors: A
authors: Katagiri
authors: K
authors: K
authors: Okamoto
authors: R
authors: R
authors: Thompson
authors: D A
authors: DA
authors: Bereiter
mesh_terms: D000818:Animals; D058787:GABA-A Receptor Antagonists / Q000494:pharmacology; D007034:Hypothalamus, Posterior / Q000187:drug effects / Q000502:physiology*; D007765:Lacrimal Apparatus / Q000187:drug effects / Q000502:physiology*; D008297:Male; D010775:Photic Stimulation / Q000379:methods*; D051381:Rats; D017207:Rats, Sprague-Dawley; D013666:Tears / Q000187:drug effects / Q000502:physiology*; D014276:Trigeminal Nerve / Q000187:drug effects / Q000502:physiology*
chemical_list: D058787:GABA-A Receptor Antagonists
references: Pharmacol Biochem Behav. 1983 Jun;18(6):901-7
references: 6136987
references: Pain. 2010 May;149(2):235-242
references: 20206444
references: Ophthalmic Plast Reconstr Surg. 1999 Nov;15(6):384-9
references: 10588244
references: Curr Opin Neurol. 2008 Jun;21(3):323-30
references: 18451717
references: J Neuroophthalmol. 1995 Jun;15(2):90-4
references: 7550935
references: J Comp Neurol. 1987 Jun 1;260(1):98-126
references: 3496365
references: J Comp Neurol. 1996 Oct 28;374(4):607-31
references: 8910738
references: Exp Brain Res. 1980;40(1):79-87
references: 7418761
references: Brain Res. 1978 Mar 31;143(3):521-32
references: 647376
references: J Neurosci. 2006 Mar 29;26(13):3589-93
references: 16571767
references: J Anat. 2001 Apr;198(Pt 4):463-72
references: 11327208
references: Nat Med. 1999 Jul;5(7):836-8
references: 10395332
references: Pain. 2004 Jun;109(3):367-378
references: 15157698
references: Am J Ophthalmol. 1951 Sep;34(9):1294-1300
references: 14877953
references: Confin Neurol. 1975;37(1-3):285-90
references: 1093792
references: Am J Physiol. 1988 Apr;254(4 Pt 2):R680-7
references: 3354717
references: J Physiol. 1995 May 15;485 ( Pt 1):113-20
references: 7658366
references: Brain Res Rev. 2009 Apr;60(1):214-25
references: 19146877
references: J Neuroophthalmol. 2012 Mar;32(1):68-81
references: 22330853
references: Neurosci Lett. 2007 Jan 10;411(2):92-7
references: 17110030
references: J Neurophysiol. 1999 Nov;82(5):2092-107
references: 10561390
references: Neuroscience. 2009 Jun 2;160(4):858-64
references: 19285114
references: Curr Opin Neurol. 2011 Jun;24(3):197-202
references: 21467933
references: Cephalalgia. 2006 Sep;26(9):1043-50
references: 16919054
references: J Comp Neurol. 2004 Feb 16;469(4):581-607
references: 14755537
references: Pain. 1991 Dec;47(3):299-304
references: 1784500
references: Pain. 2000 Sep;87(3):241-251
references: 10963904
references: Lancet. 1998 Jul 25;352(9124):275-8
references: 9690407
references: Ophthalmologica. 2011;226(3):151-6
references: 21832827
references: Auton Neurosci. 2011 Nov 16;165(1):67-79
references: 21071284
references: Am J Physiol Regul Integr Comp Physiol. 2001 Sep;281(3):R683-98
references: 11506981
references: Headache. 1989 Jun;29(6):373-6
references: 2759845
references: J Comp Neurol. 1998 Oct 12;400(1):125-44
references: 9762871
references: Prog Retin Eye Res. 2012 Sep;31(5):377-406
references: 22580107
references: CLAO J. 1983 Jul-Sep;9(3):281-9
references: 6413088
references: Lancet Neurol. 2009 Aug;8(8):755-64
references: 19608101
references: Exp Eye Res. 2010 Mar;90(3):388-96
references: 20004193
references: Brain Res. 1981 Feb 9;206(1):39-50
references: 6162522
references: J Neurosci. 1999 Apr 15;19(8):3171-82
references: 10191330
references: Pain. 2005 Sep;117(1-2):30-9
references: 16043293
references: Neuroscience. 2012 Dec 27;227:144-53
references: 23036619
references: Pain. 1979 Oct;7(2):135-145
references: 523171
references: Trends Neurosci. 1992 Dec;15(12):475-81
references: 1282743
references: J Comp Neurol. 2004 Jan 1;468(1):24-56
references: 14648689
references: Pain. 2009 Nov;146(1-2):84-90
references: 19679396
references: Ocul Immunol Inflamm. 2007 Mar-Apr;15(2):99-104
references: 17558834
references: J Neurosurg. 1970 Dec;33(6):689-707
references: 5488801
references: J Neurosci. 2004 Apr 28;24(17):4224-32
references: 15115818
references: Neurology. 2008 Oct 14;71(16):1275-82
references: 18852443
references: Mult Scler. 2009 Nov;15(11):1322-8
references: 19812115
references: J Comp Neurol. 1987 Jul 15;261(3):450-9
references: 3112189
references: Cephalalgia. 2008 Jul;28(7):799-803
references: 18547217
references: Pain. 2009 Oct;145(3):358-363
references: 19674842
references: Neuropharmacology. 1987 May;26(5):407-17
references: 3037412
references: Behav Brain Res. 1998 Apr;92(1):97-102
references: 9588689
references: Ophthalmic Plast Reconstr Surg. 2000 Sep;16(5):326-9
references: 11021380
references: Eur J Neurosci. 2012 Dec;36(11):3492-9
references: 22937868
references: Cephalalgia. 2008 Jul;28(7):787-97; discussion 798
references: 18547215
references: J Pharmacol Exp Ther. 1979 Sep;210(3):311-5
references: 480182