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Calcitonin gene-related peptide in the developing mouse olfactory system
Developmental Bram Research, 54 (1990) 295-298
295
Elsevier
BRESD 611367
Calcitonin gene-related peptide in the developing mouse olfactory system Harriet Baker Cornell Untversuv Medtcal College, The Burke Rehabdttatlon Center, Whzte Plams, N Y 10605 (U S A )
(Accepted 27 March 1990) Key words Olfactory marker protein, Tyrosme hydroxylase, Phenotypic expression, Rodent, Olfactory epithelium
The development of calcltonm gene-related pepttde (CGRP) was investigated m the mouse olfactory system The peptlde was not found in olfactory receptor neurons in embryos examined from gestatlonal day 13 (El3) to El8 but was present in other brain regions and in peripheral tissues At El8, CGRP-immunoreactive fibers, presumably of tngeminal, not olfactory receptor cell, origin were observed within the lamina proprla These data suggest that m wvo CGRP does not act through olfactory receptor neurons to regulate phenotypic expression m the olfactory bulb A number of studies have now established that expression of the dopamine phenotype in olfactory bulb (OB) juxtaglomerular neurons is under transneuronal regulation from peripheral olfactory afferent receptor cell lnnervatton (see ref. 3 for review). Both chemical and surgical deafferentatlon result in decreased levels of dopamine In addition, activity, immunoreactlvity, and m R N A levels are reduced for tyrosine hydroxylase (TH), the rate-limiting enzyme in dopamme biosynthesm. Recent experiments, employing cultured embryonic mouse olfactory bulb, supported a role for calcitonin gene related peptide (CGRP), a 37-amino acid neuropeptide, in the induction of the OB dopamme phenotype during development, and by extension in the control of TH expression in the adult 5 C G R P is derived by alternative RNA splicing of the same gene which encodes calcitonln 1'13. The peptide is highly expressed m discrete regions of the neural axis including the olfactory system 9"13 In order to be imphcated in the regulation of TH enzyme expression In the adult, CGRP would have to be localized within olfactory afferent receptor cells and their axons, since lesion of the receptor neurons profoundly alters the dopamine phenotype in the OB Several recent communications indicated that C G R P lmmunoreactwity in adults is found in fibers within the olfactory mucosa and is colocalized with substance p6 7.14 yet there has been no demonstration of C G R P in olfactory receptor cells or their processes. Alternatively, if CGRP is important only to the induction of the dopamine phenotype during development, then it m~ght be expressed transiently in receptor
cells exclusively during gestation. The current studies investtgated the prenatal distribution of CGRP in the mouse olfactory system in order to ascertain if the peptlde can be implicated in the reduction of the dopamine phenotype in vivo, as in vitro. Embryos were obtained by caesarian section from timed pregnant CD-1 mice (Charles River Breeding Laboratories, Kingston, NY) which were anesthetized with Nembutal (30 mg/kg, i p.). Gestational day 13 embryos (El3) were immersed in fixative (4% buffered, 0.1 M phosphate buffer, formaldehyde generated from paraformaldehyde) for 6-12 h Embryos from El5 to E18 were perfused with saline followed by the above fixative, and then postfixed for several hours. All tissue was cryoprotected in 30% sucrose, 30/~m cryostat sections were collected on subbed slides, and tissue was immunoreacted as previously described z using specific antlsera to CGRP (provided by Susan Amara and Randy Blakely, Yale University, New Haven, CT) or olfactory marker protein (OMP, provided by Frank L Margolis, Roche Institute, Nutley, N J) OMP was utilized to demonstrate the developing receptor cell neurons and their processes in the olfactory epithelium and bulb as this protein previously was localized to these cells during embryogenesis 8 OMP was demonstrable in olfactory receptor neurons and processes from about El3 (Fig 1A,C). On the other hand, CGRP-hke immunoreactivlty was not found in the receptor cells or their processes at El3 (Fig. 1B,D) or any gestational age (Fig 2B,D). However, CGRP immunoreactwe cells and fibers were observed in the spinal cord
Correspondence H Baker, Cornell Umverslty Medical College, The Burke Rehablhtatlon Center, 785 Mamaroneck Avenue, White Plains, NY 10605, U S A
0165-3806/90/$03 50 © 1990 Elsevter Sctence Pubhshers B V (Blomedtcal Dwlslon)
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Fig 2 Dark-field ( A , B ) and bright-field (C,D) photomicrographs of OMP- and CGRP-lmmunoreactive elements in adjacent sections from an E l 8 mouse A robust OMP-lmmunostamed cells and fibers are observed in the olfactory mucosa, in nerve fascicles in the lamina proprla (lp) which innervate the OB, and within the olfactory nerve layer of the OB (ob). Some fibers also exist in deeper layers of the OB Large arrow indicates a region illustrated at higher magnification in C B in a section adjacent to that in A , CGRP-immunostalned fibers are observed m the lamina propria (lp) and in some fibers which approach the OB (small arrows) At this age stained centrifugal afferents are not yet present in the OB Neither receptor cells nor their processes appear to contain C G R P lmmunoreactivity Data from other laboratories 6'7't°'12'i4 suggest that the stained processes in the lamina propria are of trigemmal origin Large arrow indicates region illustrated at higher magnification in D C large numbers of O M P immunoreactlve receptor cells are found in the eplthehal layer (oe) and large bundles of fibers are observed m the lamina propria D' a few varicose fibers lmmunostamed with C G R P are observed in the lamina propna, but no receptor cell staining is observed m the epithelial layer Bar = 260 pm for A and B and 40/~m for C and D
Fig. 1 0 M P and C G R P immunoreactivitles in the mouse OB. A OMP lmmunoreactlvity In the embryonic day 13 ( E l 3 ) mouse occurs in many receptor cells m the olfactory mucosa (small arrows) and in stamed fibers (arrowheads) which reach the region of the presumptive OB. As it was not possible to perfuse the E13 mouse, darkly stained blood cells are apparent outside the neuroeplthehum, but are distinct from the OMP-lmmunostalned receptor cells and fibers Large arrow indicates region illustrated at higher magnification in C B in a section adjacent to that in A , CGRP-lmmunoreactlvity is not observed in olfactory receptor cells in the E13 mouse or at any gestational age Large arrow indicates regions illustrated at higher magnification in D. C' numerous OMP-immunostamed olfactory receptor cells, some with apical dendrites, are apparent at this magnification D no CGRP-contalnlng cells or processes are observed even at higher magmficatlon E. at E l 3 , CGRP-contalnlng neurons (arrows) are observed in the ventral horn of the spinal cord F in the adult mouse, CGRP-immunostalned fibers are observed m the olfactory nerve layer (onl, curved arrows) and in centrifugal fibers (straight arrow) of unknown origin. The CGRP-lmmunoreactlve fibers surround but do not enter the glomerulus (gl). a, anterior, cv, cerebral vesicle, nc, nasal cavity, v, ventral A , B , bar = 1 7 0 # m C - E , bar = 4 0 / ~ m , E bar = 20/~m
298 at E l 3 (Fig. 1E). In the lamina propria, C G R P - i m m u noreactive fibers, presumably of trigemmal origin, were observed first at E15. A t this age, other regions of the central and peripheral nervous systems, including the spinal cord, medulla oblongata and dorsal root ganglia, exhibited C G R P immunoreactivity. The n u m b e r and l m m u n o s t a m l n g intensity of these fibers increased with
or in the adult. The reason for this difference m expression ts not clear. The same antiserum was used m both studies and, as reported for the adult, the antiserum stained fibers within the developing olfactory mucosa and other brain regions. Given the absence of an appropriate
advancmg gestational age (Fig. 2B,D). In the adult OB,
spatial-temporal expression of C G R P lmmunoreactlv~D within receptor cells in vlvo, the reported presence of C G R P in vitro Is either an artifact of the culture
fibers containing C G R P were seen within the olfactory nerve layer (Fig. lF). The origin of these fibers has not
condittons or a misldentfflcation of the C G R P stained cells as receptor n e u r o n s
been d e t e r m i n e d , but substance P q m m u n o r e a c t l v e fibers
Thus, while C G R P may influence the expression of T H in cultures of mouse OB, the pept~de does not appear
in the nerve layer previously were ascribed a trtgeminal origin 6 10,i2. Centrifugal afferent fibers l m m u n o s t a i n e d
to play a role in the development or m a i n t e n a n c e of the
with C G R P also were observed surrounding the olfactory
dopamine phenotype in VlVO since ~t Is not present in the
glomeruh in adult mice (Fig. 1F). These processes were not observed even in E18 embryos and may develop
olfactory afferent n e u r o n s or their processes either at appropriate gestatlonal ages when T H Is first observed (E18), or in the adult mouse.
postnatally, as was observed for serotonm immunoreactlvity in the rat li These data demonstrate, that in contrast to the locahzatton of C G R P to receptor cells m vitro 5, the peptlde could not be d e m o n s t r a t e d within neurons of the olfactory epithelium m vivo, either during embryogenesls
The author would hke to thank Mr Jorge Lugo for his technical assistance, Mr Jordan Pontell for photographic assistance, and Drs. Donna Stone and Charles Greer for comment~ on the manuscript Supported by DC00336 and MH44043
1 Amara, S G , Jonas, V, Rosenfeld, M G , Ong, E S and Evans, R M , Alternative RNA processing in calotonm gene expression generates mRNAs encoding &fferent polypeptlde products, Nature, 298 (1982) 240-244 2 Baker, H., Species differences in the distribution ot substance P and tyroslne hydroxylase lmmunoreactlvity m the olfactory bulb, J. Comp Neurol, 252 (1986) 206-226 3 Baker, H , Neurotransmltter plasticity m the luxtaglomerular cells of the olfactory bulb In EL Margohs and TV Getchell (Eds), Molecular Neurobtology of the Olfactory S wtem, Plenum, New York, 1988, pp 185-216 4 Baker, H , Grillo, M and Margolls, F L , Biochemical and ~mmunocytochem~calcharacterization of olfactory marker protern m the rodent central nervous system J Comp Neurol, 285 (1989) 246-261 5 Dems-Domnl, S , Expression of dopammergic phenotypes in the mouse olfactory bulb reduced by the calcltonm gene-related peptlde, Nature, 339 (1989) 701-703 6 Finger, T E , Getchell, M.L., Getchell, T V. and Kmnamon, J C , Affector and effector functions of peptlderglc mnervation of the nasal cavity In B G Green, J R. Mason and M R Kare (Eds), Chemwal Irntatlon m the Nose and Mouth, Dekker, New York, in press 7 Finger, T E , Womble, M and Silver, W.L, Innervatton of the vomeronasal organ of rodents by peptlderglc nerve fibers
Jmmunoreactive for substance P and calotonln gene-related peptlde (CGRP), Chem. Senses, 14 (1989) 698 8 Farbman, A I , Prenatal development of mammalian olfactory receptor cells, Chem. Sense3, 11 (1986) 3-18 9 Gibson, S J , Polak, J.M, Bloom, S R . Sabate, I.M. Mulderry, P M , Ghatel, M.A, McGregor, G P., Mornson, J EB., Kelly. J S. Evans, R M and Rosenfeld, M G , Calcitonm gene-retated peptlde lmmunoreactlvity m the spinal cord of man and of eight other speoes, J Neuroscl, 4 (1984) 3101-3111 10 Hokfelt, T, Ketlerth, J O , Nllsson, G and Pernow, B , Substance P locahzat~on m the central nervous system and in some primary sensory neurons, Sctence, 190 (1975) 889-890 ll McLean, J H and Shlpley, M T, Serotonerglc afferents to the rat olfactory bulb II Changes in fiber distribution during development, J Neurosct, 7 (1987) 3029-3039 12 Papka, R E and Matuhnois, D H , Association of substance Pqmmunoreact~ve nerves with the murme olfactory mucosa, Cell Tissue Res, 230 (1983) 517-525 13 Rosenfeld, M G , Mermod, J J , Amara, S G , Swanson, L.W, Sawchenko, P E , Rivier, J , Vale, WW and Evans, R.M., Production of a novel neuropeptlde encoded by the CT gene via tissue-specific RNA processing, Nature, 304 (1983) 129-135 14 Silver, W L , Farley, L G , Womble, M and Finger, T E , The etfect of neonatal capsmcm admlmstratlon on tngermnal nerve fibers m the nasal cavity, ('hem Senses. 14 (1989) 748.
295
Elsevier
BRESD 611367
Calcitonin gene-related peptide in the developing mouse olfactory system Harriet Baker Cornell Untversuv Medtcal College, The Burke Rehabdttatlon Center, Whzte Plams, N Y 10605 (U S A )
(Accepted 27 March 1990) Key words Olfactory marker protein, Tyrosme hydroxylase, Phenotypic expression, Rodent, Olfactory epithelium
The development of calcltonm gene-related pepttde (CGRP) was investigated m the mouse olfactory system The peptlde was not found in olfactory receptor neurons in embryos examined from gestatlonal day 13 (El3) to El8 but was present in other brain regions and in peripheral tissues At El8, CGRP-immunoreactive fibers, presumably of tngeminal, not olfactory receptor cell, origin were observed within the lamina proprla These data suggest that m wvo CGRP does not act through olfactory receptor neurons to regulate phenotypic expression m the olfactory bulb A number of studies have now established that expression of the dopamine phenotype in olfactory bulb (OB) juxtaglomerular neurons is under transneuronal regulation from peripheral olfactory afferent receptor cell lnnervatton (see ref. 3 for review). Both chemical and surgical deafferentatlon result in decreased levels of dopamine In addition, activity, immunoreactlvity, and m R N A levels are reduced for tyrosine hydroxylase (TH), the rate-limiting enzyme in dopamme biosynthesm. Recent experiments, employing cultured embryonic mouse olfactory bulb, supported a role for calcitonin gene related peptide (CGRP), a 37-amino acid neuropeptide, in the induction of the OB dopamme phenotype during development, and by extension in the control of TH expression in the adult 5 C G R P is derived by alternative RNA splicing of the same gene which encodes calcitonln 1'13. The peptide is highly expressed m discrete regions of the neural axis including the olfactory system 9"13 In order to be imphcated in the regulation of TH enzyme expression In the adult, CGRP would have to be localized within olfactory afferent receptor cells and their axons, since lesion of the receptor neurons profoundly alters the dopamine phenotype in the OB Several recent communications indicated that C G R P lmmunoreactwity in adults is found in fibers within the olfactory mucosa and is colocalized with substance p6 7.14 yet there has been no demonstration of C G R P in olfactory receptor cells or their processes. Alternatively, if CGRP is important only to the induction of the dopamine phenotype during development, then it m~ght be expressed transiently in receptor
cells exclusively during gestation. The current studies investtgated the prenatal distribution of CGRP in the mouse olfactory system in order to ascertain if the peptlde can be implicated in the reduction of the dopamine phenotype in vivo, as in vitro. Embryos were obtained by caesarian section from timed pregnant CD-1 mice (Charles River Breeding Laboratories, Kingston, NY) which were anesthetized with Nembutal (30 mg/kg, i p.). Gestational day 13 embryos (El3) were immersed in fixative (4% buffered, 0.1 M phosphate buffer, formaldehyde generated from paraformaldehyde) for 6-12 h Embryos from El5 to E18 were perfused with saline followed by the above fixative, and then postfixed for several hours. All tissue was cryoprotected in 30% sucrose, 30/~m cryostat sections were collected on subbed slides, and tissue was immunoreacted as previously described z using specific antlsera to CGRP (provided by Susan Amara and Randy Blakely, Yale University, New Haven, CT) or olfactory marker protein (OMP, provided by Frank L Margolis, Roche Institute, Nutley, N J) OMP was utilized to demonstrate the developing receptor cell neurons and their processes in the olfactory epithelium and bulb as this protein previously was localized to these cells during embryogenesis 8 OMP was demonstrable in olfactory receptor neurons and processes from about El3 (Fig 1A,C). On the other hand, CGRP-hke immunoreactivlty was not found in the receptor cells or their processes at El3 (Fig. 1B,D) or any gestational age (Fig 2B,D). However, CGRP immunoreactwe cells and fibers were observed in the spinal cord
Correspondence H Baker, Cornell Umverslty Medical College, The Burke Rehablhtatlon Center, 785 Mamaroneck Avenue, White Plains, NY 10605, U S A
0165-3806/90/$03 50 © 1990 Elsevter Sctence Pubhshers B V (Blomedtcal Dwlslon)
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Fig 2 Dark-field ( A , B ) and bright-field (C,D) photomicrographs of OMP- and CGRP-lmmunoreactive elements in adjacent sections from an E l 8 mouse A robust OMP-lmmunostamed cells and fibers are observed in the olfactory mucosa, in nerve fascicles in the lamina proprla (lp) which innervate the OB, and within the olfactory nerve layer of the OB (ob). Some fibers also exist in deeper layers of the OB Large arrow indicates a region illustrated at higher magnification in C B in a section adjacent to that in A , CGRP-immunostalned fibers are observed m the lamina propria (lp) and in some fibers which approach the OB (small arrows) At this age stained centrifugal afferents are not yet present in the OB Neither receptor cells nor their processes appear to contain C G R P lmmunoreactivity Data from other laboratories 6'7't°'12'i4 suggest that the stained processes in the lamina propria are of trigemmal origin Large arrow indicates region illustrated at higher magnification in D C large numbers of O M P immunoreactlve receptor cells are found in the eplthehal layer (oe) and large bundles of fibers are observed m the lamina propria D' a few varicose fibers lmmunostamed with C G R P are observed in the lamina propna, but no receptor cell staining is observed m the epithelial layer Bar = 260 pm for A and B and 40/~m for C and D
Fig. 1 0 M P and C G R P immunoreactivitles in the mouse OB. A OMP lmmunoreactlvity In the embryonic day 13 ( E l 3 ) mouse occurs in many receptor cells m the olfactory mucosa (small arrows) and in stamed fibers (arrowheads) which reach the region of the presumptive OB. As it was not possible to perfuse the E13 mouse, darkly stained blood cells are apparent outside the neuroeplthehum, but are distinct from the OMP-lmmunostalned receptor cells and fibers Large arrow indicates region illustrated at higher magnification in C B in a section adjacent to that in A , CGRP-lmmunoreactlvity is not observed in olfactory receptor cells in the E13 mouse or at any gestational age Large arrow indicates regions illustrated at higher magnification in D. C' numerous OMP-immunostamed olfactory receptor cells, some with apical dendrites, are apparent at this magnification D no CGRP-contalnlng cells or processes are observed even at higher magmficatlon E. at E l 3 , CGRP-contalnlng neurons (arrows) are observed in the ventral horn of the spinal cord F in the adult mouse, CGRP-immunostalned fibers are observed m the olfactory nerve layer (onl, curved arrows) and in centrifugal fibers (straight arrow) of unknown origin. The CGRP-lmmunoreactlve fibers surround but do not enter the glomerulus (gl). a, anterior, cv, cerebral vesicle, nc, nasal cavity, v, ventral A , B , bar = 1 7 0 # m C - E , bar = 4 0 / ~ m , E bar = 20/~m
298 at E l 3 (Fig. 1E). In the lamina propria, C G R P - i m m u noreactive fibers, presumably of trigemmal origin, were observed first at E15. A t this age, other regions of the central and peripheral nervous systems, including the spinal cord, medulla oblongata and dorsal root ganglia, exhibited C G R P immunoreactivity. The n u m b e r and l m m u n o s t a m l n g intensity of these fibers increased with
or in the adult. The reason for this difference m expression ts not clear. The same antiserum was used m both studies and, as reported for the adult, the antiserum stained fibers within the developing olfactory mucosa and other brain regions. Given the absence of an appropriate
advancmg gestational age (Fig. 2B,D). In the adult OB,
spatial-temporal expression of C G R P lmmunoreactlv~D within receptor cells in vlvo, the reported presence of C G R P in vitro Is either an artifact of the culture
fibers containing C G R P were seen within the olfactory nerve layer (Fig. lF). The origin of these fibers has not
condittons or a misldentfflcation of the C G R P stained cells as receptor n e u r o n s
been d e t e r m i n e d , but substance P q m m u n o r e a c t l v e fibers
Thus, while C G R P may influence the expression of T H in cultures of mouse OB, the pept~de does not appear
in the nerve layer previously were ascribed a trtgeminal origin 6 10,i2. Centrifugal afferent fibers l m m u n o s t a i n e d
to play a role in the development or m a i n t e n a n c e of the
with C G R P also were observed surrounding the olfactory
dopamine phenotype in VlVO since ~t Is not present in the
glomeruh in adult mice (Fig. 1F). These processes were not observed even in E18 embryos and may develop
olfactory afferent n e u r o n s or their processes either at appropriate gestatlonal ages when T H Is first observed (E18), or in the adult mouse.
postnatally, as was observed for serotonm immunoreactlvity in the rat li These data demonstrate, that in contrast to the locahzatton of C G R P to receptor cells m vitro 5, the peptlde could not be d e m o n s t r a t e d within neurons of the olfactory epithelium m vivo, either during embryogenesls
The author would hke to thank Mr Jorge Lugo for his technical assistance, Mr Jordan Pontell for photographic assistance, and Drs. Donna Stone and Charles Greer for comment~ on the manuscript Supported by DC00336 and MH44043
1 Amara, S G , Jonas, V, Rosenfeld, M G , Ong, E S and Evans, R M , Alternative RNA processing in calotonm gene expression generates mRNAs encoding &fferent polypeptlde products, Nature, 298 (1982) 240-244 2 Baker, H., Species differences in the distribution ot substance P and tyroslne hydroxylase lmmunoreactlvity m the olfactory bulb, J. Comp Neurol, 252 (1986) 206-226 3 Baker, H , Neurotransmltter plasticity m the luxtaglomerular cells of the olfactory bulb In EL Margohs and TV Getchell (Eds), Molecular Neurobtology of the Olfactory S wtem, Plenum, New York, 1988, pp 185-216 4 Baker, H , Grillo, M and Margolls, F L , Biochemical and ~mmunocytochem~calcharacterization of olfactory marker protern m the rodent central nervous system J Comp Neurol, 285 (1989) 246-261 5 Dems-Domnl, S , Expression of dopammergic phenotypes in the mouse olfactory bulb reduced by the calcltonm gene-related peptlde, Nature, 339 (1989) 701-703 6 Finger, T E , Getchell, M.L., Getchell, T V. and Kmnamon, J C , Affector and effector functions of peptlderglc mnervation of the nasal cavity In B G Green, J R. Mason and M R Kare (Eds), Chemwal Irntatlon m the Nose and Mouth, Dekker, New York, in press 7 Finger, T E , Womble, M and Silver, W.L, Innervatton of the vomeronasal organ of rodents by peptlderglc nerve fibers
Jmmunoreactive for substance P and calotonln gene-related peptlde (CGRP), Chem. Senses, 14 (1989) 698 8 Farbman, A I , Prenatal development of mammalian olfactory receptor cells, Chem. Sense3, 11 (1986) 3-18 9 Gibson, S J , Polak, J.M, Bloom, S R . Sabate, I.M. Mulderry, P M , Ghatel, M.A, McGregor, G P., Mornson, J EB., Kelly. J S. Evans, R M and Rosenfeld, M G , Calcitonm gene-retated peptlde lmmunoreactlvity m the spinal cord of man and of eight other speoes, J Neuroscl, 4 (1984) 3101-3111 10 Hokfelt, T, Ketlerth, J O , Nllsson, G and Pernow, B , Substance P locahzat~on m the central nervous system and in some primary sensory neurons, Sctence, 190 (1975) 889-890 ll McLean, J H and Shlpley, M T, Serotonerglc afferents to the rat olfactory bulb II Changes in fiber distribution during development, J Neurosct, 7 (1987) 3029-3039 12 Papka, R E and Matuhnois, D H , Association of substance Pqmmunoreact~ve nerves with the murme olfactory mucosa, Cell Tissue Res, 230 (1983) 517-525 13 Rosenfeld, M G , Mermod, J J , Amara, S G , Swanson, L.W, Sawchenko, P E , Rivier, J , Vale, WW and Evans, R.M., Production of a novel neuropeptlde encoded by the CT gene via tissue-specific RNA processing, Nature, 304 (1983) 129-135 14 Silver, W L , Farley, L G , Womble, M and Finger, T E , The etfect of neonatal capsmcm admlmstratlon on tngermnal nerve fibers m the nasal cavity, ('hem Senses. 14 (1989) 748.