Spontaneous activity of rat pretectal nuclear complex neurons in vitro

Springer Science and Business Media LLC - Tập 5 - Trang 1-11 - 2004
Nora Prochnow1, Matthias Schmidt1
1Allgemeine Zoologie & Neurobiologie, Ruhr-Universität Bochum, Bochum, Germany

Tóm tắt

Neurons in the mammalian pretectum are involved in the control of various visual and oculomotor tasks. Because functionally independent pretectal cell populations show a wide variation of response types to visual stimulation in vivo, they may also differ in their intrinsic properties when recorded in vitro. We therefore performed whole-cell patch clamp recordings from neurons in the caudal third of the pretectal nuclear complex in frontal brain slices obtained from 3 to 6 week old hooded rats and tried to classify pretectal neurons electrophysiologically. Pretectal neurons showed various response types to intracellular depolarizations, including bursting and regular firing behavior. One population of pretectal nuclear complex neurons could be particularly distinguished from others because they displayed spontaneous activity in vitro. These cells had more positive resting potentials and higher input resistances than cells that were not spontaneously active. The maintained firing of spontaneously active pretectal cells was characterized by only small variances in interspike intervals and thus showed a regular temporal patterning. The firing rate was directly correlated to the membrane potential. Removing excitatory inputs by blockade of AMPA and/or NMDA receptors did not change the spontaneous activity. Simultaneous blockade of excitatory and inhibitory synaptic input by a substitution of extracellular calcium with cobalt neither changed the firing rate nor its temporal patterning. Each action potential was preceeded by a depolarizing inward current which was insensitive to calcium removal but which disappeared in the presence of tetrodotoxin. Our results indicate that a specific subpopulation of pretectal neurons is capable of generating maintained activity in the absence of any external synaptic input. This maintained activity depends on a sodium conductance and is independent from calcium currents.

Tài liệu tham khảo

Klooster J, Vrensen GF, Muller LJ, Van der Want JJ: Efferent projections of the olivary pretectal nucleus in the albino rat subserving the pupillary light reflex and related reflexes. A light microscopic tracing study. Brain Res. 1995, 688: 34-46. 10.1016/0006-8993(95)00497-E.

Kourouyan HD, Horton JC: Transneuronal retinal input to the primate Edinger-Westphal nucleus. J Comp Neurol. 1997, 381: 68-80. 10.1002/(SICI)1096-9861(19970428)381:1<68::AID-CNE6>3.0.CO;2-I.

Collewijn H: Direction-selective units in the rabbit's nucleus of the optic tract. Brain Res. 1975, 100: 489-508. 10.1016/0006-8993(75)90154-7.

Kato I, Harada K, Hasegawa T, Igarashi T, Koike Y, Kawasaki T: Role of the nucleus of the optic tract in monkeys in relation to optokinetic nystagmus. Brain Res. 1986, 364: 12-22. 10.1016/0006-8993(86)90982-0.

Cohen B, Reisine H, Yokota JI, Raphan T: The nucleus of the optic tract. Its function in gaze stabilization and control of visual-vestibular interaction. Ann NY Acad Sci. 1992, 656: 277-296.

Fischer WH, Schmidt M, Hoffmann KP: Saccade-induced activity of dorsal lateral geniculate nucleus X- and Y- cells during pharmacological inactivation of the cat pretectum. Vis Neurosci. 1998, 15: 197-210. 10.1017/S0952523898151106.

Schmidt M, Sudkamp S, Wahle P: Characterization of pretectal-nuclear-complex afferents to the pulvinar in the cat. Exp Brain Res. 2001, 138: 509-519. 10.1007/s002210100738.

Lugo-Garcia N, Kicliter E: Superior colliculus efferents to five subcortical visual system structures in the ground squirrel. Brain Res. 1987, 426: 131-141. 10.1016/0006-8993(87)90432-X.

Vargas CD, Volchan E, Hokoc JN, Pereira A, Bernardes RF, Rocha-Miranda CE: On the functional anatomy of the nucleus of the optic tract-dorsal terminal nucleus commissural connection in the opossum (Didelphis marsupialis aurita). Neuroscience. 1997, 76: 313-321. 10.1016/S0306-4522(96)00356-9.

Baldauf ZB, Wang XP, Wang S, Bickford ME: Pretectotectal pathway: an ultrastructural quantitative analysis in cats. J Comp Neurol. 2003, 464: 141-158. 10.1002/cne.10792.

Young MJ, Lund RD: The retinal ganglion cells that drive the pupilloconstrictor response in rats. Brain Res. 1998, 787: 191-202. 10.1016/S0006-8993(97)01473-X.

Klauer S, Sengpiel F, Hoffmann KP: Visual response properties and afferents of nucleus of the optic tract in the ferret. Exp Brain Res. 1990, 83: 178-189. 10.1007/BF00232207.

Sanghera MK, Trulson ME, German DC: Electrophysiological properties of mouse dopamine neurons: in vivo and in vitro studies. Neuroscience. 1984, 12: 793-801. 10.1016/0306-4522(84)90171-4.

Nakanishi H, Kita H, Kitai ST: Electrical membrane properties of rat subthalamic neurons in an in vitro slice preparation. Brain Res. 1987, 437: 35-44. 10.1016/0006-8993(87)91524-1.

Ujihara H, Akaike A, Sasa M, Takaori S: Electrophysiological evidence for cholinoceptive neurons in the medial vestibular nucleus: studies on rat brain stem in vitro. Neurosci Lett. 1988, 93: 231-235. 10.1016/0304-3940(88)90087-0.

Häusser M, Clark BA: Tonic synaptic inhibition modulates neuronal output pattern and spatiotemporal synaptic integration. Neuron. 1997, 19: 665-678. 10.1016/S0896-6273(00)80379-7.

Simpson JI, Giolli RA, Blanks RHI: The pretectal nuclear complex. In: Neuroanatomy of the oculomotor system. Edited by: Büttner-Ennever J. 1988, Amsterdam, Elsevier, 335-364.

Hoffmann KP, Stone J: Retinal input to the nucleus of the optic tract of the cat assessed by antidromic activation of ganglion cells. Exp Brain Res. 1985, 59: 395-403. 10.1007/BF00230920.

Hoffmann KP, Fischer WH: Directional effect of inactivation of the nucleus of the optic tract on optokinetic nystagmus in the cat. Vision Res. 2001, 41: 3389-3398. 10.1016/S0042-6989(01)00184-5.

Dodt HU, Zieglgänsberger W: Visualizing unstained neurons in living brain slices by infrared DIC-videomicroscopy. Brain Res. 1990, 537: 333-336. 10.1016/0006-8993(90)90380-T.