Flocculus

Streptomyces flocculus Streptomyces fradiae Streptomyces griseus... 

Grusser-Cornehls U (1995) Responses of flocculus and vestibular nuclei neurons in Weaver mutant mice (B6CBA wv/wv) to combined head and body rotation. Exp Brain Res 707 26-33. 

CAS 3930-19-6. C23I I2 ,N4()8. An antibiotic derived from Streptomyces flocculus. Dark-brown, rectangular crystals. 

Methyltryptophan (92) has been shown to be a biosynthetic precursor of the antibiotic streptonigrin (93) in Streptomyces flocculus (J.K. Allen, K.D. Barrow and A.J. Jones, J.chem.Soc.Chem. Comm., 1979, 280). The antibiotic itself has been studied by other groups of chemists ( S.J. Gould and S.M. Weinreb, Fortschr.chem. Org.Naturst., 1982, 41, ofJ7). Another antibiotic, streptonlgrone (95), is metabolised hy Streptomyces sp. (A.J. Kelt, R.W. Rickards and J.-P. Wu, Antibiotics, 1985, 38, 516), but lavendamycin (94), a related alkaloid from S. lavendulae (T.W. Doyle et al.. Tetrahedron Letters, 1981, 4595), does not appear to be its natural precursor. Lavendamycin has been synthesised (A.S. Kende and F.H. Ebetino, Tetrahedron Letters, 1984, 923). 

Fig. 19. Schematic illustration of the zonal distribution of somatostatin immunoreactive Purkinje cells at different levels of the cerebellum of a 21 day old rat. Drawings have been made from frontal, cresyl-violet stained sections. Each dot represents 2-5 cells. Abbreviations 5-9, cerebellar lobules V-IX 4V, 4th ventricle COP, copula pyramis CR2, crus 2, ansiform lobule FL, flocculus PFL, paraflocculus PM, primary fissure SF, secondary fissure. Villar et al. (1989).

Fig. 69. A. Monoclonal antibody Rat-302 recognizes a subset of neurons, later identified as unipolar brush cells, restricted to the granular layer of the flocculus and the vermis of rat cerebellum (arrows), whereas in other areas of the cerebellum no positive cells are found. B. In contrast, antibody Rat-303 recognizes Golgi-II cells in the granular layer (g) in the entire cerebellum. C. Rat-302 also recognizes Purkinje cells outside the caudal vermis and the flocculus. D. Rat-302 positive cells in the vermis. E and F. Unipolar brush cells recognized by Rat-302 have a round cell body and short dendrites ending in a spray of appendages (arrows), g, granular layer m, molecular layer p, Purkinje cell layer. Scale bars 500 fim in A and B, 50 /rm in C and D. 10 /rm in E and F. Hockfield (1987).

Fig. 80. Schematic diagram of the unfolded rat cerebellar cortex, showing the distribution of fibers and terminals (dots) arising from the ventral tegmental area. CP, opula pyramis Crus 1, crus I ansiform lobule Crus II, crus II ansiform lobule FI, flocculus PFI, paraflocculus Pm, paramedian lobule Simplex, simple lobule. Ikai et al. (1992).

Fig. 98. Cerebellum of the cat. The continuity in the folial chains of vermis and hemisphere is indicated by lines in the diagrams. CRI = crus I of the ansiform lobule CRII = crus II of the ansiform lobule FLO = flocculus LOB ANT/POST = anterior/posterior lobe PFLD = dorsal paraflocculus PFLV = ventral parafloc-culus PMD = paramedian lobule SI = simple lobule VII-X = lobules of the caudal vermis. Bigare (1980).

Fig. 99. Cerebellum of Macaca fascicularis. a. Anterior aspect, b. Ventral aspect, c. Caudal aspect, d. Dorsal aspect. Regions without cortex, where the white matter comes to the surface, are indicated with light hatching. Heavy hatching indicates cross section of the cerebellar peduncles, solid black indicates roof of the fourth ventricle in b. CrI = Crus I of the ansiform lobule CrII = crus II of the ansiform lobule FLO = flocculus fpl = posterolateral fissure PFLD = dorsal parafloculus PFLV = ventral paraflocculus PMD(cop) = paramedian lobule (copula pyramidis) SI = lobulus simplex.

The (central) cerebellar nuclei and the lateral vestibular nucleus of Deiters receive the axons of the Purkinje cells of the cerebellar cortex and serve as the main output stations of the cerebellum. The vermis and the flocculus also project to other vestibular nuclei, but here the Purkinje cell axons compete with vestibular root fibers, intrinsic and commissural vestibular connections and projections from the medial cerebellar nucleus and, therefore, are not the dominant afferent system. 

One group of small neurons in the rhesus monkey, which was described by Langer (1985) under the name of the basal interstitial nucleus (see Section 5.1.), displays uniform and strong AChE activity. These small cells lie dispersed in the white matter of the flocculus and the nodulus and ventral to the dentate and the posterior interposed nucleus, in the roof of the fourth ventricle. The presence of strongly AChE-positive but ChAT-negative small cells in the white matter of the flocculus of the rat, that may correspond to Langer s interstitial nucleus, was noticed by Komei et al. (1983). 

Fig. 123. Diagram of the corticonuclear projection in the cat. Based on retrograde labelling of Purkinje cells and their axons after injections of HRP in their target nuclei. A = A zone A = Anterior interposed nucleus ANS = ansiform lobule B = B zone C1-C3 = C1-C3 zones CRII = crus II of the ansiform lobule D1-D2 = D1-D2 zones DV = descendng vestibular nucleus F = fastigial nucleus FLOC = flocculus IP = posterior interposed nucleus L = lateral eerebellar nucleus LOB POST = posterior lobe LOB ANT = anterior lobe LV = Deiters nucleus MVmc = magnocellular medial vestibular nucleus MVpc = parvicellular medial vestibular nucleus PFL = paraflocculus PFLD = dorsal paraflocculus PFLV = ventral paraflocculus PMED = paramedian lobule SV = superior vestibular nucleus I-X = lobules I-X. Bigare (1980).

Fig. 125. White matter compartments Cj, D, and D2 in the paraflocculus of the cat in transverse, AChE-reacted sections. Note concentric arrangement of the compartments in the dorsal and the ventral paraflocculus. A = caudalmost section D = rostralmost section. ANS = ansiform lobule brp = brachium pontis Cl-3 = Cl-3 compartments crest = restiform body D = dentate nucleus D (1,2) = D (1,2) compartments F = fastigial nucleus FLO = flocculus lA = anterior interposed nucleus IP = posterior interposed nucleus PFLD = dorsal paraflocculus PFLV = ventral paraflocculus PMD = paramedian lobule.

The C2 compartment is clearly related to the posterior interposed nucleus. Rostrally it is located dorsal to the anterior interposed nucleus, in the intermediate part of the hemisphere. From the posterior interposed nucleus the C2 compartment extends dorso-laterally into the ansiform lobule, caudally into the paramedian lobule and ventrolater-ally into the paraflocculus and the flocculus (Fig. 148). In the anterior lobe C2 is located between the C, and C3 compartments. Ventrally C, and C3 fuse and are related to the... 

Fig. 126. Zones and compartments in the paraflocculus of the ferret. Cj, D, and Dj zones indicated on surface of caudal (A) and rostral (C) aspect of the paraflocculus with different shadings. B and D. Reconstructions of the compartmental borders in the cerebellar white matter. ANS = ansiform lobule FLO = flocculus PFLD = dorsal paraflocculus PFLV = ventral paraflocculus PMD = paramedian lobule. Voogd (1969). Drawings by J. Tinkelenberg.

Fig. 127. Distribution of acetylcholinesterase at the borders of white matter compartments in the anterior lobe of Macaco fascicularis A-C3 = A-C, zones be = brachium conjunctivum bp = brachium pontis FLO = flocculus lA = anterior interposed nucleus m = midline PFLV = ventral paraflocculus.

Fig. 128. Diagrammatic representation of the corticonuclear projection of lobule V in Galago. There are at least six identifiable corticonuclear projection zones in the lobule V cortex. The vermis consists of zones A and B, the intermediate cortex of three zones C, - C3 and the lateral cortex of a single D zone, f = flocculus IC = intermediate cortex LC = lateral cortex Ivn = lateral vestibular nucleus 1-nia = lateral anterior interposed nucleus m - nia = medial anterior interposed nucleus m - nip = medial posterior interposed nucleus nl = lateral cerebellar nucleus nm = medial nucleus vc = vermal cortex. Haines and Rubertone (1979)...

A majority of the Purkinje cells and many of the stellate and basket cells in the molecular layer reacted with the antibody against CSADC. These cells were distributed in a midline-band and 3 pairs of CSADC-positive and -negative bands on either side. The bands increased in width in the dorsal part of the anterior lobe (Fig. 130). In the vermis of the posterior lobe similar bands existed but were less distinct. Two CSADC-positive bands were present in the hemisphere. The flocculus and the paraflocculus contained the highest number of CSADC-positive Purkinje cells, but they were not zonally distributed. 

Fig. 129. Schematic drawing of the distribution of motilin-immunoreactive (M-i) Purkinje cells (open triangles) and glutamic acid decarboxylase-immunoreactive (GAD-i) Purkinje cells (filled circles) in a coronal section of rat cerebellum. M-i cells and GAD-i cells are both more concentrated in the flocculus and the paraflocculus than elsewhere. Both cell types occur in the vermis and participate in the formation of the sagittal microzones (arrows). M-i terminal axon projections in the deep cerebellar nuclei are heaviest in the dentate (D left side) and GAD-i projections are heaviest in the lateral vestibular nucleus (LV right side). 1 = interposed nucleus F = fastigial nucleus. Chan-Palay et al. (1981).

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