Abstract
This study investigated the synaptic interactions between hypoglossal motoneurons that project to the genioglossus muscle and substance P (SP) containing immunoreactive nerve terminals. Cholera toxin B conjugated to horseradish peroxidase (CTB-HRP) was injected into the right half of the genioglossus muscle in four anesthetized cats. Two days later, the animals were perfused with acrolein fixative. Tetramethylbenzidine (TMB) was the chromogen used to detect retrogradely labeled cells containing CTB-HRP. The tissues were then processed for immunocytochemisty using an antiserum raised against SP with diaminobenzidine (DAB) as the chromogen. At the light microscopic level, labeled cells were observed primarily ipsilaterally in ventral and ventrolateral subdivisions of the hypoglossal nucleus. The majority of these labeled cells were observed at the level of the area postrema. At the electron microscopic level, SP-like immunoreactive nerve terminals formed synaptic contacts with retrogradely labeled dendrites and perikarya. Nineteen percent of the terminals that contacted retrogradely labeled cells contained SP. These are the first ultrastructural studies demonstrating synaptic interactions between protruder hypoglossal motoneurons and SP terminals. These studies demonstrate that hypoglossal motoneurons which innervate the major protruder muscle of the tongue, the genioglossus muscle, may be modulated by SP. Thus, SP may play a role in the control of protrusive movements of the tongue acting via neurokinin receptors.
Similar content being viewed by others
References
Aldes LD, Chronister RB, Marco LA (1988a) Distribution of glutamic acid decarboxylase and gamma-aminobutyric acid in the hypoglossal nucleus in the rat. J Neurosci Res 19:343–348
Aldes LD, Chronister RB, Shelton C, Haycock JW, Marco LA, Wong DL (1988b) Catecholamine innervation of the rat hypoglossal nucleus. Brain Res Bull 21:305–312
Aldes LD, Chronister RC, Marco LA, Haycock JW, Thibault J (1988c) Differential distribution of biogenic amines in the hypoglossal nucleus of the rat. Exp Brain Res 73:305–314
Aldes LD, Marco LA, Chronister RB (1989) Serotonin-containing axon terminals in the hypoglossal nucleus of the rat. An immuno-electronmicroscopic study. Brain Res Bull 23:249–256
Aldes LD, Shaw B, Chronister RB, Haycock JW (1990) Catecholamine-containing axon terminals in the hypoglossal nucleus of the rat: an immuno-electronmicroscopic study. Exp Brain Res 81:167–178
Altschuler SM, Bao X, Miselis RR (1994) Dendritic architecture of hypoglossal motoneurons projecting to extrinsic tongue musculature in the rat. J Comp Neurol 342:538–550
Barnard JW (1940) The hypoglossal complex of vertebrates. J Comp Neurol 72:489–524
Berger AJ, Bayliss DA, Viana F (1992) Modulation of neonatal rat hypoglossal motoneuron excitability by serotonin. Neurosci Lett 143:164–168
Boone TB, Aldes LD (1984) The ultrastructure of two distinct neuron populations in the hypoglossal nucleus of the rat. Exp Brain Res 54:321–326
Chen Z, Hedner J, Hedner T (1990a) Substance P in the ventrolateral medulla oblongata regulates ventilatory responses. J Appl Physiol 68:2631–2639
Chen Z, Hedner J, Hedner T (1990b) Local effects of substance P on respiratory regulation in the rat medulla oblongata. J Appl Physiol 68:693–699
Connaughton M, Priestley JV, Sofroniew MV, Eckenstein NF, Cuello AC (1986) Inputs to motoneurones in the hypoglossal nucleus of the rat: light and electron microscopic immunocytochemistry for choline acetyltransferase, substance P and enkephalins using monoclonal antibodies. Neurosci 17:205–224
Cooper MH (1981) Neurons of the hypoglossal nucleus of the rat. Otolaryngol Head Neck Surg 89:10–15
Cuello AC, Kanazawa (1978) The distribution of substance P immunoreactive fibers in the rat central nervous system. J Comp Neurol 178:129–156
Gatti PJ, Richardson KA (2001) Synaptic interactions of retrogradely labeled genioglossus motoneurons with substance P-like immunoreactive terminals in the cat: a double labeling immunoelectron microscopic study. Respir Res 2: P28
Gatti PJ, Shirahata M, Johnson TA, Massari VJ (1995) Synaptic interactions of substance P immunoreactive nerve terminals in the baro- and chemoreceptor reflexes. Brain Res 693:133–147
Gatti PJ, Johnson TA, Shirahata M, Massari VJ (1996) Synaptic interactions of retrogradely labeled hypoglossal motoneurons with substance P-like immunoreactive nerve terminals in the cat: a dual-labeling electron microscopic study. Exp Brain Res 110:175–182
Gatti PJ, Lewellyn-Smith IJ, Sun Q-J, Chalmers J, Pilowsky PM (1999) Substance P-immunoreactive boutons closely appose inspiratory protruder hypoglossal motoneurons in the cat. Brain Res 834:155–159
Guo Y, Goldberg SJ, McClung JR (1996) Compartmental organization of styloglossus and hyoglossus motoneurons in the hypoglossal nucleus of the rat. Brain Res 728:277–280
Henry JN, Manaker S (1998) Co-localization of substance P or enkephalin in serotonergic afferents to the hypoglossal nucleus. J Comp Neurol 391:491–508
Hinrichsen CFL, Weston S (1999) Substance P in the hypoglossal nucleus of the rat. Arch Oral Biol 44:683–691
Kachidian P, Poulat P, Marlier L, Privat A (1991) Immunohistochemical evidence for the co-existence of substance P, thyrotropin releasing hormone, gamma-aminobutyric acid, met-enkephalin and leu-enkephalin in the serotonergic neurons of the caudal raphe nuclei: a dual labeling study in the rat. J Neurosci Res 30:521–530
Krammer EB, Rath T, Lischka MF (1979) Somatotopic organization of the hypoglossal nucleus: a HRP study in the rat. Brain Res 170:533–537
Kubin L, Tojima H, Davies RO, Pack AI (1992) Serotonergic excitatory drive to hypoglossal motoneurons in the decerebrate cat. Neurosci Lett 139:243–248
Ljungdahl A, Hokfelt T, Nilsson G (1978) Distribution of substance P-like immunoreactivity in the central nervous system of the rat-I. Cell bodies and nerve terminals. Neurosci 3:861–943
Llewellyn-Smith IJ, Pilowsky P, Minson JB (1993) The tungstate stabilized tetramethylbenzidine reaction for light and electron microscopic immunocytochemistry and for revealing biocytin-filled neurons. J Neurosci Meth 26:27–40
Massari VJ, Shirahata M, Johnson TA, Lauenstein J-M Gatti PJ (1998) Carotid sinus nerve terminals which are substance P immunoreactive are found in the dorsolateral nucleus of the tractus solitarius. Brain Res 785:329–340
McClung F, Goldberg SJ (1999) Organization of motoneurons in the dorsal hypoglossal nucleus that innervate the retrusor muscles of the tongue in the rat. Anat Rec 254:222–230
Miyazaki T, Yoshida Y, Hirano M, Shin T, Kanaseki T (1981) Central location of the motoneurons supplying the thyrohyoid and the geniohyoid muscles as demonstrated by horseradish peroxidase method. Brain Res 219:423–427
Odutola AB (1976) Cell grouping and Golgi architecture of the hypoglossal nucleus of the rat. Exp Neurol 52:356–371
Peters AA, Palay SL, Webster HD (1990) Fine structure of the nervous system: neurons and their supporting cells. Oxford Univ Press, New York
Sokoloff AJ (1991) Musculotopic organization of the hypoglossal nucleus in the grass frog, Rana pipiens. J Comp Neurol 308:505–512
Takeuchi Y, Kojima M, Matsuura T, Sano Y (1983) Serotonergic innervation on the motoneurons in the mammalian brainstem. Anat Embryol 167:321–333
Uemura M, Matsuda K, Kume M, Takeuchi Y, Matsushima R, Mizuno N (1979) Topographical arrangement of hypoglossal motoneurons: an HRP study in the cat. Neurosci Lett 13:99–104
Uemura-Sumi M, Mizuno N, Nomura S, Iwahori N, Takeuchi Y, Matsushima R (1981) Topographical representation of the hypoglossal nerve branches and tongue muscles in the hypoglossal nucleus of macaque monkeys. Neurosci Lett 22:31–35
Uemura-Sumi M, Itoh M, Mizuno N (1988) The distribution of hypoglossal motoneurons in the dog, rabbit and rat. Anat Embryol (Berl) 177:389–394
Wan XS, Trojanowski JQ, Gonatas JO, Liu CN (1982) Cytoarchitecture of the extranuclear and commissural dendrites of hypoglossal nucleus neurons as revealed by conjugates of horseradish peroxidase with cholera toxin. Exp Neurol 78:167–175
Yasuda K, Robinson DM, Selvaratnam SR, Walsh CW, McMorland AJ, Funk GD (2001) Modulation of hypoglossal motoneuron excitability by NK1 receptor activation in the neonatal mouse. J Physiol (Lond) 554:447–464
Acknowledgements
This work was supported by grants from the NIDCD (DC4001 to Dr. Gatti). Additional support was obtained from the Burroughs Wellcome Fund, American Physiological Society, Department of Pharmacology and Howard University College of Medicine. The authors would like to thank Drs. Virginia Pickel, Teri Milner and John Massari for their assistance in interpreting the photomicrographs, Dr. Musa Haxhiu for reviewing this manuscript and Dr. Greg Funk for helpful insight.
Author information
Authors and Affiliations
Corresponding author
Rights and permissions
About this article
Cite this article
Richardson, K.A., Gatti, P.J. Genioglossal hypoglossal motoneurons contact substance P-like immunoreactive nerve terminals in the cat: a dual labeling electron microscopic study. Exp Brain Res 154, 327–332 (2004). https://doi.org/10.1007/s00221-003-1672-5
Received:
Accepted:
Published:
Issue Date:
DOI: https://doi.org/10.1007/s00221-003-1672-5