Summary
The suprachiasmatic nucleus (SCN) of female rats was surveyed with microelectrodes under urethane anaesthesia. In rats with bilateral transection of the optic tracts, repetitive three pulses of 100 Hz applied to the contralateral optic nerve excited 8 and inhibited 11 other of the 86 SCN units examined. Transection of the optic tract did not significantly influence frequency of occurrence of the SCN units that were excited or inhibited by stimulation of the optic nerve. Certain SCN units responded to both of contralateral and ipsilateral stimulations of the optic nerve, indicating that bilateral visual inputs converge on the same single SCN neurones. Oscillatory responses with a period of 100–200 msec were occasionally produced by stimulation of the optic nerve. Flash stimuli with relatively weak intensity, even insufficient for producing wavelets in electroretinograms, produced an excitation and inhibition in SCN units. The mean firing rates were significantly altered by either electrical or flash stimuli repeated 500 times at 0.97 Hz in those units which showed no transitory response. Some of the SCN neurones receiving visual inputs were identified to be the tuberoinfundibular neurone and some other SCN neurones were found to receive converging inputs both from the optic nerve and from the axon collaterals of tuberoinfundibular neurones.
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References
Babel, J., Stangos, N., Korol, S., Spiritus, M.: Ocular electrophysiology. A clinical and experimental study of electroretinogram, electro-oculogram visual evoked response, p. 11. Stuttgart: Thieme 1977
Brown, K.T.: The electroretinogram: its components and their origins. In: UCLA forum in medical sciences, No. 8: the retina. Morphology, function and clinical characteristics (eds. B.R. Straatsma, M.O. Hall, R.A. Allen, F. Crescitelli) pp. 319–378. Berkeley: University of California Press 1969
Colman, D.R., Scalia, F., Cabrales, E.: Light and electron microscopic observations on the anterograde transport of horseradish peroxidase in the optic pathway in the mouse and rat. Brain Res.102, 156–163 (1976)
Frank, K., Becker, M.C.: Microelectrodes for recording and stimulation. In: Physical techniques in biological research, Vol. 5 (ed. W.L. Nastuk), pp. 22–87. New York: Academic Press 1964
Green, D.G.: Light adaptation in the rat retina: evidence for two receptor mechanisms. Science174, 598–600 (1971)
Groos, G., Mason, R.: Maintained discharge of rat suprachiasmatic neurons at different adaptation levels. Neurosci. Lett.8, 59–64 (1978)
Güldner, F.-H.: Synaptology of the rat suprachiasmatic nucleus. Cell Tiss. Res.165, 509–544 (1976)
Güldner, F.-H., Wolff, J.R.: Retinal afferents from Gray-type I and type-II synapses in the suprachiasmatic nucleus (rat). Exp. Brain Res.32, 83–89 (1978)
Hendrickson, A.E., Wagoner, N., Cowan, W.M.: An autoradiographic and electron microscopic study of retino-hypothalamic connections. Z. Zellforsch.135, 1–26 (1972)
König, J.F., Klippel, R.A.: The rat brain. A stereotaxic atlas of the forebrain and lower parts of the brain stem. Baltimore: Williams and Wilkins 1963
Lincoln, D.W., Church, J., Mason, C.A.: Electrophysiological activation of suprachiasmatic neurones by changes in retinal illumination. Acta Endocr. (Copenh.) [Suppl.]119, 184 (1975)
Mai, J.K., Junger, E.: Quantitative autoradiographic light- and electron microscopic studies on the retinohypothalamic connections in the rat. Cell Tiss. Res.183, 221–237 (1977)
Mason, C.A., Lincoln, D.W.: Visualization of retino-hypothalamic projections in the rat. J. Endocr.67, 33–34P (1975)
Mason, C.A., Lincoln, D.W.: Visualization of the retino-hypothalamic projection in the rat by cobalt precipitation. Cell Tiss. Res.168, 117–131 (1976)
Moore, R.Y., Karapas, F., Lenn, N.J.: A retinohypothalamic projection in the rat. Anat. Rec.169, 382–383 (1971)
Moore, R.Y., Lenn, N.J.: A retinohypothalamic projection in the rat. J. Comp. Neurol.146, 1–14 (1972)
Nishino, H., Koizumi, K., Brooks, C.McC.: The role of suprachiasmatic nuclei of the hypothalamus in the production of circadian rhythm. Brain Res.112, 45–59 (1976)
Rall, W., Shepherd, G.M., Reese, T.S., Brightman, M.W.: Dendrodendritic synaptic pathway for inhibition in the olfactory bulb. Exp. Neurol.14, 44–56 (1966)
Ribak, C.E., Peters, A.: An autoradiographic study of the projections from the lateral geniculate body of the rat. Brain Res.92, 341–368 (1975)
Sawaki, Y.: Retinohypothalamic projection: electrophysiological evidence for the existence in female rats. Brain Res.120, 336–341 (1977)
Sawaki, Y., Yagi, K.: Electrophysiological identification of cell bodies of the tubero-infundibular neurones in the rat. J. Physiol. (Lond.)230, 75–85 (1973)
Sawaki, Y., Yagi, K.: Inhibition and facilitation of antidromically identified tubero-infundibular neurones following stimulation of the median eminence in the rat. J. Physiol. (Lond.)260, 447–460 (1976)
Singer, W., Creutzfeldt, O.D.: Reciprocal lateral inhibition of on- and off-center neurones in the lateral geniculate body of the cat. Exp. Brain Res.10, 311–330 (1970)
Sousa-Pinto, A., Castro-Correia, J.: Light microscopic observations on the possible retino-hypothalamic projection in the rat. Exp. Brain Res.11, 515–527 (1970)
Swanson, L.W., Cowan, W.M., Jones, E.G.: An autoradiographic study of the efferent connections of the ventral lateral geniculate nucleus in the albino rat and the cat. J. Comp. Neurol.156, 143–164 (1974)
Szentágothai, J.: The structure of the synapse in the lateral geniculate body. Acta Anat.55, 166–185 (1963)
Tsukahara, N., Bando, T., Kiyohara, T.: The properties of the reverberating circuit in the brain. In: Neuroendocrine control (eds. K. Yagi, S. Yoshida), pp. 3–26. Tokyo: University of Tokyo Press 1973
Yagi, K., Sawaki, Y.: Recurrent inhibition and facilitation: demonstration in the tubero-infundibular system and effects of strychnine and picrotoxin. Brain Res.84, 155–159 (1975)
Yagi, K., Sawaki, Y.: Electrophysiological characteristics of identified tubero-infundibular neurons. Neuroendocrinology26, 50–64 (1978)
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Sawaki, Y. Suprachiasmatic nucleus neurones: Excitation and inhibition mediated by the direct retino-hypothalamic projection in female rats. Exp Brain Res 37, 127–138 (1979). https://doi.org/10.1007/BF01474259
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DOI: https://doi.org/10.1007/BF01474259