Nucleus prepositus hypoglossi

Shortly after the discovery of Ih in the heart, a very similar current was identified in the brain (29), and not long thereafter, two simultaneous works (30,31) reported that serotonin facilitated Ih in neurons of the thalamus and the nucleus prepositus hypoglossi. Like the effect of norepinephrine in the heart, this effect of serotonin was mediated via cAMP and involved a shift in the voltage dependence of 4 The net effect of this shift in voltage dependence is an increase in the net amount of inward current contributed by HCN channels at a given voltage and thus results in a slow depolarization of the resting membrane potential. 

Fig. 165. The vestibulo-olivary projection in the cat. Localization of terminal fields with antegrade axonal transport of pHJleucine. A. Contralateral projection from the superior vestibular nucleus. B. Ipsilateral projection from the medial vestibular nucleus. C. Bilateral projections from the nucleus prepositus hypoglossi. MAO = medial accessory olive PO = principal olive. Gerrits et al. (1985a).

Widespread projections of the nucleus prepositus hypoglossi and neighbouring perihypoglossal nuclei terminate bilaterally with an ipsilateral predominance in the vermis, the flocculus and the paraflocculus and in the cerebellar nuclei (see McCrea and... 

Fig. 201. HRP- and cholineacetyl transferase (ChAT)-labelled neurons in the vestibular complex of rabbit following an HRP injection into the left ventral paraflocculus and immunocytochemistry with an antibody against ChAT. (A) The black and stippled areas correspond to dense and less dense HRP concentrations. The solid arrows delinate borders between the flocculus, ventral and dorsal paraflocculus. (B) 1-5 are rostral-caudal brainstem sections through the left vestibular complex spaced approximately 400 fim apart. The filled circles correspond to HRP- and ChAT-labelled neurons. The open circles correspond to ChAT-labelled neurons only. The filled diamonds correspond to HRP-labelled neurons only. MVN and DVN, medial and descending vestibular nucleus NPH, nucleus prepositus hypoglossi X, nucleus X ICP, inferior cerebellar peduncle N V and tr V, trigeminal nucleus and tract ION, inferior olivary nucleus N VII, facial nucleus VII, facial nerve DMN X, dorsal motor nucleus of the vagus CE, external cuneate nucleus CN, cochlear nucleus Pyr, pyramidal tract FI, flocculus dPf, dorsal paraflocculus vPf, ventral paraflocculus. Barmack et al. (1992b).

De Zeeuw Cl, Wentzel P, Mugnaini E. (1993) Fine structure of the dorsal cap of the inferior olive and its GABAergic and non-GABAergic input from the nucleus prepositus hypoglossi in rat and rabbit. J. Comp. Neurol., 327, 63—82. 

Yamamoto M (1978) Localization of rabbit s flocculus Purkinje cells projeeting to the cerebellar lateral nucleus and the nucleus prepositus hypoglossi investigated by means of the horseradish peroxidase retrograde axonal transport. Neuroscl Lett., 7, 197-202. 

Yingcharoen K, Rinvik E (1983) Ultrastruetural demonstration of a projection from the flocculus to the nucleus prepositus hypoglossi in the cat. Exp. Brain Re.[Pg.369]

---