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Involvement of substance P in photic induction of c-Fos in the suprachiasmatic nucleus of Syrian hamsters
S240
AADC mRNA COEXPRESSES VASOPRESSIN mRNA BUT NOT SOMATOSTATIN 2215 mRNA IN NEURONS OF THE RAT SUPRACHIASMATIC NUCLEUS. FYOSI * . TOMOYUKI MATSUDA **v. . . . . ** Anestheslalngy of Me~ Kvoto PrefaGtural. . Unwers& . * . _ku! Kvoto 603. JaDan: Third Owwon of I’IeDartment of . . . . e. Kobe Unlver&y School of Medlclne Vasopressin producing neurons and somatostatin producing neurons are both distributed in the dorsomedial to intermediate portion of the rat suprachiasmatic nucleus (SCN). Their peptide content and mRNA levels are known to show diurnal rhythm regardless of the light-dark cycle. The aromatic L-amino acid decarboxylase (AADC) containing neurons are found in the same dorsomedial components of the SCN and recently our laboratory has revealed that AADC mRNA represents endogenous circadian variation. In this study, we investigated the possibility of the coexpression of AADC and vasopressin or somatostatin at mRNA level in the SCN by the double staining in situ hybridization method. AADC mRNA was visualized as blue deposits by digoxigenin labeled cRNA probes and vasopressin or somatostatin mRNA was detected as silver grains by 35Slabeled cRNA probes. In the rat SCN, most of AADC mRNA positive neurons also coexpressed vasopressin mRNA, but they very rarely coexpressed somatostatin mRNA. The present study suggests that circadian clock regulates the expression of mRNA of AADC and vasopressin located in the same neuron of the SCN.
2216
NFURO-GLIAL INTERACTION IN THE RAT SUPRACHIASNATICNUCLEUS -DOUBLE LABELING LIGHT AND ELECTRON MICROSCOPIC IMMUNOCYTOCHEMISTRYYASV
Byoto 602, JaDan. In the present study, we aimed to scrutinize the morphological interaction between astroglial elements and neuronal elements in the rat suprachiasmatic nucleus(SCN) by double labeling light and electron microscopic immunocytochemistryusing antibodies against glial fibrillary acidic protein(GFAP),vasoactive intestinal peptide(VIP) and arginine vasopressin(AVP). GFAP-like immunoreactivity was found throughout the SCN, particularly in the ventral portion. GFAP-like immunoreactive (GFAP-LI) processes were found to surround some portion of VIP-like immunoreactive(VIP-LI)or AVP-like i.mmunoreactive(AVP-LI) neuronal soma and processes. Some of GFAP-LI processes were observed to intervene neuronal soma. GFAP-LI processes were also detected to lie between neurons and capillaries, and seem to play a role for blood-brain barrier. The above findings suggest that astrocytes with GFAP-like immunoreactivity play a significant roles for satellite or blood-brain barriers by close interaction with neurons such as VIP-LI and AVP-LI neurons and capillaries in the rat SCN.
2217
INVOLVEMENT OF SUPRACHIASMATIC &WSJYUKI s . . 001 ofnoroO60.
SUBSTANCE P IN PHOTIC INDUCTION NUCLEUS OF SYRIAN HAMSTERS. KEN-ICHI HONMA. BqUnnmt of Jw
OF
C-FOS
IN
THE
SubstanceP(SP)is acandidateoftheneurotransmitteror neuromodulator of the retinohypothaiamic tract(RHT)which is Ithasbeen thedirect projection from the retina tothesuprachiasmatic nucleus (SCN),a circadian oscillator inrodents. suggested in neurophysiological studies that SP modulates glutamatergic transmission in the RHT to mediate retinal information to the SCN to produce phase-shift or entrainment of the oscillator to lightdark cycle. Immediate early gene c-fos has been well demonstrated to be induced in the SCN with light exposure, and suggested to play an important role in photic entrainment of the oscillator. It raises the possibility that SP may be involved in mediating the light information to induce the expression of c-fos in the SCN cells. We therefore examined effects of SP receptor antagonist, spantide, on light-induced Fos-like immunoreactivity (Fos-lir) in the SCN cells of Syrian hamster. The spantide (0, 0.1 and 1 mh4 in saline) was injected i.c.v. 5 min before 15 min light exposure at 4 hrs after the dark onset of LD14:lO cycle. Animals were perfused 45 min after the light exposure, and then the brains were sectioned and roceeded for Fos protein immunohistochemistry using avidin-biotin method. The light exposure induced Fos-lir in the SC K of animals injected saline with the pattern described previously. The light-induced Fos-lir was inhibited with pretreatment of spantide in a dose-related manner and in an anatomically distinctive way. The higher dose of spantide blocked light-induced Fos-lir in the rostra1 and central of the SCN. It however failed to block Fos-lir in the ventral portion of caudal SCN, while it inhibited in the dorsal part of the caudal SCN. These results suggest that SP receptor is involved in mediating light information to induce Fos expression in hamster SCN, and that different neurotransmitter systems may be involved in photic-induction of Fos in different parts of hamster SCN.
AADC mRNA COEXPRESSES VASOPRESSIN mRNA BUT NOT SOMATOSTATIN 2215 mRNA IN NEURONS OF THE RAT SUPRACHIASMATIC NUCLEUS. FYOSI * . TOMOYUKI MATSUDA **v. . . . . ** Anestheslalngy of Me~ Kvoto PrefaGtural. . Unwers& . * . _ku! Kvoto 603. JaDan: Third Owwon of I’IeDartment of . . . . e. Kobe Unlver&y School of Medlclne Vasopressin producing neurons and somatostatin producing neurons are both distributed in the dorsomedial to intermediate portion of the rat suprachiasmatic nucleus (SCN). Their peptide content and mRNA levels are known to show diurnal rhythm regardless of the light-dark cycle. The aromatic L-amino acid decarboxylase (AADC) containing neurons are found in the same dorsomedial components of the SCN and recently our laboratory has revealed that AADC mRNA represents endogenous circadian variation. In this study, we investigated the possibility of the coexpression of AADC and vasopressin or somatostatin at mRNA level in the SCN by the double staining in situ hybridization method. AADC mRNA was visualized as blue deposits by digoxigenin labeled cRNA probes and vasopressin or somatostatin mRNA was detected as silver grains by 35Slabeled cRNA probes. In the rat SCN, most of AADC mRNA positive neurons also coexpressed vasopressin mRNA, but they very rarely coexpressed somatostatin mRNA. The present study suggests that circadian clock regulates the expression of mRNA of AADC and vasopressin located in the same neuron of the SCN.
2216
NFURO-GLIAL INTERACTION IN THE RAT SUPRACHIASNATICNUCLEUS -DOUBLE LABELING LIGHT AND ELECTRON MICROSCOPIC IMMUNOCYTOCHEMISTRYYASV
Byoto 602, JaDan. In the present study, we aimed to scrutinize the morphological interaction between astroglial elements and neuronal elements in the rat suprachiasmatic nucleus(SCN) by double labeling light and electron microscopic immunocytochemistryusing antibodies against glial fibrillary acidic protein(GFAP),vasoactive intestinal peptide(VIP) and arginine vasopressin(AVP). GFAP-like immunoreactivity was found throughout the SCN, particularly in the ventral portion. GFAP-like immunoreactive (GFAP-LI) processes were found to surround some portion of VIP-like immunoreactive(VIP-LI)or AVP-like i.mmunoreactive(AVP-LI) neuronal soma and processes. Some of GFAP-LI processes were observed to intervene neuronal soma. GFAP-LI processes were also detected to lie between neurons and capillaries, and seem to play a role for blood-brain barrier. The above findings suggest that astrocytes with GFAP-like immunoreactivity play a significant roles for satellite or blood-brain barriers by close interaction with neurons such as VIP-LI and AVP-LI neurons and capillaries in the rat SCN.
2217
INVOLVEMENT OF SUPRACHIASMATIC &WSJYUKI s . . 001 ofnoroO60.
SUBSTANCE P IN PHOTIC INDUCTION NUCLEUS OF SYRIAN HAMSTERS. KEN-ICHI HONMA. BqUnnmt of Jw
OF
C-FOS
IN
THE
SubstanceP(SP)is acandidateoftheneurotransmitteror neuromodulator of the retinohypothaiamic tract(RHT)which is Ithasbeen thedirect projection from the retina tothesuprachiasmatic nucleus (SCN),a circadian oscillator inrodents. suggested in neurophysiological studies that SP modulates glutamatergic transmission in the RHT to mediate retinal information to the SCN to produce phase-shift or entrainment of the oscillator to lightdark cycle. Immediate early gene c-fos has been well demonstrated to be induced in the SCN with light exposure, and suggested to play an important role in photic entrainment of the oscillator. It raises the possibility that SP may be involved in mediating the light information to induce the expression of c-fos in the SCN cells. We therefore examined effects of SP receptor antagonist, spantide, on light-induced Fos-like immunoreactivity (Fos-lir) in the SCN cells of Syrian hamster. The spantide (0, 0.1 and 1 mh4 in saline) was injected i.c.v. 5 min before 15 min light exposure at 4 hrs after the dark onset of LD14:lO cycle. Animals were perfused 45 min after the light exposure, and then the brains were sectioned and roceeded for Fos protein immunohistochemistry using avidin-biotin method. The light exposure induced Fos-lir in the SC K of animals injected saline with the pattern described previously. The light-induced Fos-lir was inhibited with pretreatment of spantide in a dose-related manner and in an anatomically distinctive way. The higher dose of spantide blocked light-induced Fos-lir in the rostra1 and central of the SCN. It however failed to block Fos-lir in the ventral portion of caudal SCN, while it inhibited in the dorsal part of the caudal SCN. These results suggest that SP receptor is involved in mediating light information to induce Fos expression in hamster SCN, and that different neurotransmitter systems may be involved in photic-induction of Fos in different parts of hamster SCN.