Summary
The morphological and physiological integrity of abducens internuclear interneurons was evaluated following chemical removal of their almost exclusive target, i.e. the contralateral medial rectus motoneuron population. Motoneuron death was induced by toxic ricin injection into the ipsilateral medial rectus muscle. The main advantage of this method is that target removal is not associated with presynaptic axon damage. The activity of identified abducens internuclear interneurons was recorded before and after target removal during spontaneous eye movements in the chronic cat preparation. Several abnormalities and a remarkable decrease in eye position and velocity sensitivities were observed in the discharge pattern of these neurons for a period of 15–20 days following target removal. After that time all recorded interneurons behaved normally. A parallel morphological study showed the absence of any abducens internuclear interneuron death. These results indicate that, after a critical period, the abducens internuclear interneuron population recovers its normal behavior following target removal with no evidence of neuronal loss.
Similar content being viewed by others
References
Aguayo AJ (1986) Axonal regeneration in the adult mammalian central nervous system: anatomical and functional studies. In: Tsukade Y (ed) Molecular genetics in developmental neurobiology. Japan Scientific Societies Press, Tokyo, pp 259–274
Akagi Y (1978) The localization of the motor neurons innervating the extraocular muscles in the oculomotor nuclei of the cat and rabbit, using horseradish peroxidase. J Comp Neurol 181:745–762
Baker R, Highstein SM (1975) Physiological identification of interneurons and motoneurons in the abducens nucleus. Brain Res 91:292–298
Bienfang DC (1978) The course of direct projections from the abducens nucleus to the contralateral medial rectus subdivision of the oculomotor nucleus in the cat. Brain Res 145:277–289
Büttner-Ennever JA, Akert K (1981) Medial rectus subgroups of the oculomotor nucleus and their abducens internuclear input in the monkey. J Comp Neurol 197:17–27
Coggeshall RE, Chung K, Greenwood D, Hulsebosch CE (1984) An empirical method for converting nucleolar counts to neuronal numbers. J Neurosci Methods 12:125–132
Cotman CW, Nieto-Sampedro M (1984) Cell biology of synaptic plasticity. Science 225:1287–1294
Cowan WM, Fawcett JW, O'Leary DDM, Stanfield BB (1984) Regressive events in neurogenesis. Science 225:1258–1265
De la Cruz RR, Baker R, Delgado-García JM (1990) Behavior of cat abducens motoneurons following the injection of toxic ricin into the lateral rectus muscle. Brain Res (in press)
De la Cruz RR, Delgado-García JM (1990) Behavior of abducens internuclear interneurons during retrograde transneuronal degeneration in the alert cat using toxic ricin for the target death. Eur Neurosci Meeting Abstr 210:3217
Delgado-García JM, Del Pozo F, Baker R (1986a) Behavior of neurons in the abducens nucleus of the alert cat. I. Motoneurons. Neuroscience 17:929–952
Delgado-García JM, Del Pozo F, Baker R (1986b) Behavior of neurons in the abducens nucleus of the alert cat. II. Internuclear neurons. Neuroscience 17:953–973
Delgado-García JM, Escudero M, Torres B, Portillo F, Pásaro R (1988) Behavioral and morphological effects of oculomotor nucleus lesion on abducens internuclear neurons in the cat. Brain Res 443:333–337
Fuchs AF, Robison DA (1966) A method for measuring horizontal and vertical eye movement chronically in the monkey. J Appl Physiol 21:1068–1070
Highstein SM, Baker R (1978) Excitatory termination of abducens internuclear neurons on medial rectus motoneurons: relationship to syndrome of internuclear ophthalmoplegia. J Neurophysiol 41:1647–1661
Highstein SM, Karabelas A, Baker R, McCrea RA (1982) Comparison of the morphology of physiologically identified abducens motor and internuclear neurons in the cat: a light microscopic study employing the intracellular injection of horseradish peroxidase. J Comp Neurol 208:369–381
Lindsay RM (1979) Adult rat brain astrocytes support survival of both NGF-dependent and NGF-insensitive neurons. Nature 282:80–82
Maciewicz RJ, Spencer RF (1977) Oculomotor and abducens internuclear pathways in the cat. In: Baker R, Berthoz A (eds) Control of gaze by brain stem neurons: developments in neuroscience, Vol I. Elsevier/North Holland, New York, pp 99–108
McCrea RA, Strassman A, Highstein SM (1986) Morphology and physiology of abducens motoneurons and internuclear neurons intracellularly injected with horseradish peroxidase in alert squirrel monkeys. J Comp Neurol 243:291–308
Miyazaki S (1985) Location of motoneurons in the oculomotor nucleus and the course of their axons in the oculomotor nerve. Brain Res 348:57–63
Nakao S, Sasaki S (1980) Excitatory input from interneurons in the abducens nucleus to medial rectus motoneurons mediating conjugate horizontal nystagmus in the cat. Exp Brain Res 39:23–32
Pubols LM, Foglesong ME (1988) Acute and chronic effects of the neurolytic agent ricin on dorsal root ganglia, spinal cord, and nerves. J Comp Neurol 275:271–281
Sofroniew MV, Galletly NP, Isacson O, Svendsen CN (1990) Survival of adult basal forebrain cholinergic neurons after loss of target neurons. Science 247:338–342
Wiley RG, Blessing WW, Reis DJ (1982) Suicide transport: destruction of neurons by retrograde transport of ricin, abrin, and modeccin. Science 216:889–890
Wiley RG, Talman WT, Reis DJ (1983) Ricin transport distinguishes between central and peripheral neurons. Brain Res 269:357–360
Yamamoto T, Iwasaki Y, Konno H, Kudo H (1985) Primary degeneration of motor neurons by toxic lectins conveyed from the peripheral nerve. J Neurol Sci 70:327–337
Author information
Authors and Affiliations
Rights and permissions
About this article
Cite this article
De la Cruz, R.R., Baker, R. & Delgado-García, J.M. Response of adult cat abducens internuclear interneurons to selective removal of their target motoneurons. Exp Brain Res 84, 167–172 (1991). https://doi.org/10.1007/BF00231771
Received:
Accepted:
Issue Date:
DOI: https://doi.org/10.1007/BF00231771