Ricerche morfologiche sulle collaterali assoniche delle proiezioni talamiche della formazione grigia periacqueduttale

Barbaresi, Paolo   ; Conti, Fiorenzo   ; Manzoni, Tullio

Atti della Accademia nazionale dei Lincei. Rendiconti della Classe di scienze fisiche, matematiche e naturali, Série 8, Tome 73 (1982) no. 5, pp. 155-161

Résumé

Anatomical experiments were performed in 12 cats in order to ascertain whether the periaqueductal gray matter (PAG) projects to several thalamic nuclei by divergent axons collaterals originating from the same population of cells. By means of the double labeling technique based on the retrograde axonal transport of fluorescent tracers, PAG neurones were searched that contribute bifurcating axons to the following couples of thalamic nuclei: i) to the nuclei ventrales posteromediales (VPM) of the two sides; it) to the nucleus parafascicularis (Pf) and ventralis posterolateralis (VPL) of the same side; iii) to the nucleus Pf and VPM of the same side. Fast Blue (FB), Evans Blue (EB) and Nuclear Yellow (NY) were used as fluorescent tracers. In other two groups, each consisting of 4 cats, FB injections into Pf were associated with either EB or NY injections within VPL or VPM. Double labeled neurones could be found within the PAG only in animals of the first group. It is concluded that PAG sends bifurcating axons originating from the same neurons to VPM of both sides and that the set of PAG neurones projecting to VPL or VPM are separate from the set projecting to Pf.

Bibliographie

[1] Barbaresi P., Conti F. e Manzoni T. (1982) - Periaqueductal gray projection to the ventrobasal complex in the cat: an horseradish peroxidase study. «Neurosci Lett.», 30, 205-209.

[2] Basbaum A.I., Clanton C.H. e Fields H.L. (1978) - Three bulbospinal pathways from the rostral medulla of the cat: An autoradiographic study of pain modulating systems. «J. Comp. Neurol.», 179, 209-224.

[3] Bentivoglio M., Kuypers H.G.J.M. e Castman-Berrevoets C.E. (1980) - Retrograde neuronal labelling by means of bisbenzimide and Nuclear Yellow (Hoechst 769-121). Measures to prevent diffusion of the tracers out of retrogradely labelled neurons. «Neurosci. Lett.», 18, 19-24.

[4] Bentivoglio M., Kuypers H.G.J.M., Castman-Berrevoets C.E., Moewe H. e Dann O. (1980) - Two new fluorescent retrograde neuronal tracers which are transported over long distances. «Neurosci. Lett.», 18, 25-30.

[5] Chi C.C. (1970) - An experimental silver study of the ascending projections of the central gray substance and adjacent tegmentum in the rat with observations in the cat. «J. Comp. Neurol.», 139, 259-272.

[6] Comans P.E. e Snow P.J. (1981) - Ascending projections to nucleus parafascicularis of the cat. «Brain Res.», 230, 337-341.

[7] Dong W.K., Ryu H. e Wagman I.H. (1978) - Nociceptive responses in medial thalamus and their relationship to spinothalamic pathways. «J. Neurophysiol.», 41, 1592-1613.

[8] Fields H.L. e Basbaum A.I. (1978) - Brainstem control of spinal pain-transmission neurons. «Ann. Rev. Physiol.», 40, 259-272.

[9] Glaser E.M. e Van Der Loos H. (1965) - A semi-automatic computer microscope for the analysis of neuronal morphology. «IEEE Trans. Bio-Med. Engineer.», 12, 22-31.

[10] Hamilton B.L. (1973) - Projections of the nuclei of the periaqueductal gray matter in the cat. «J. Comp. Neurol.», 152, 45-58.

[11] Haimilton B.L. e Skultety F.M. (1970) - Efferent connections of the periaqueductal gray matter in the cat. «J. Comp. Neurol.», 139, 105-114.

[12] Jasper H.H. e Ajmone-Marsan C. (1954) - A stereotaxic atlas of the diencephalon of the cat, The National Research Council of Canada, Ottawa.

[13] Kenshalo D.R. Jr., Giesler G.J. Jr., Leonard R.B. e Willis W.D. (1980) - Responses of neurons in primate ventral posterior lateral nucleus to noxious stimuli. «J. Neurophysiol.», 43, 1594-1614.

[14] Kuypers H.G.J.M., Castman-Berrevoets C.E. e Padt R.E. (1977) - Retrograde axonal transport of fluorescent substances in the rat's forebrain. «Neurosci. Lett.», 6, 127-135.

[15] Liebeskind J.C., Guilbaud G., Besson J.M. e Oliveras J. (1973) - Analgesia from electrical stimulation of the periaqueductal gray matter in the cat: behavioral observations and inhibitory effects on spinal cord interneurons. «Brain Res.», 50, 441-446.

[16] Mayer D.J. (1979) — Endogenous analgesia systems: neural and behavioural mechanisms. In J.J. Bonica, J.C. Liebeskind, D. Albe-Fessard (Eds.), Advances in Pain Reserach and Therapy, vol. 3, Raven Press, New York, pp. 385-410.

[17] Mcguinness C.M. e Krauthamer G.M. (1980) — The afferent projections to the Centrum Medianum of the cat as demonstrated by retrograde transport of horseradish peroxidase, «Brain Res.», 184, 255-269.

[18] Mehler W.R. (1969) — Some neurological species differences. A posteriori. «Ann. N. Y. Acad. Sci.», 167, 424-468.

[19] Melzack R. e Casey K.L. (1968) - Sensory, motivational and central control determinants of pain: A new conceptual model. In «The Skin Sense», D.R. Keshalo (ed.), Charles C. Thomas, Springfield, 111, pp. 423—439.

[20] Nauta W.J.H. (1958) - Hippocampal projections and related neural pathways to the midbrain in the cat. «Brain», 81, 319-340.

[21] Reynolds D.V. (1969) - Surgery in the rat during electrical analgesia induced by focal brain stimulation. «Science», 164, 444-445.

[22] Ruda M.A. (1975) - An autoradiographic study of the efferent connections of the midbrain central gray in the cat. «Anat. Rec.», 181, 468-469.

[23] Shigenaga Y., Matano S., Okada K. e Sakai A. (1973) - The effects of tooth pulp stimulation in thalamus and hypothalamus of the rat. «Brain Res.», 63, 402—407.

[24] Spreafico R., Kirk C., Franceschetti S. e Avanzini G. (1980) - Brain stem projections to the pulvinar-lateralis posterior complex of the cat. «Exp. Brain Res.», 40, 209-220.

[25] Steward O. (1981) - Horseradish peroxidase and fluorescent substances and their combination with other techniques. In L. Heimer e M.J. RoBars (Eds.) «Neuroanatomical Tract-Tracing Methods», Plenum Press, New York, pp. 279-310.

[26] Tiwari R.K. e King R.B. (1974) - Fiber projections from the trigeminal nucleus caudalis in Primate (Squirrel monkey and Baboon). «J. Comp. Neurol.», 158, 191-206.

[27] Yokota T. e Hashimoto S. (1976) - Periaqueductal gray and tooth pulp afferent interaction on units in caudal medulla oblongata. «Brain Res.», 117, 508-512.