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Cerebellar afferent fibres from the dorsal motor vagal nucleus in the cat
~
Letter~, 32 (1982) 113-118 .Scientific Publishers Ireland Ltd.
I13
CEREilELLAR AFFERENT FIBRES FROM THE DORSAL MOTOR VAGAL NUCLEUS IN THE CAT
ZF,-.HUI Z H E N G ' , ESPEN DIETRICHS*" and FRED WALBERG
A~Comi¢~ Institute, Umve~ly of Oslo, Karl Johans&t. 47, Oslo ! (Norway) (Reoeivcd June 24th, 19~2; Revised version received July 5th. 1982; Accepted Jul, 10th, 1982)
Key words: dorsal motor vagal nucleus - cerebellum - retrograde transport
A biLtteral cere~ll~r afferent projection from the d.)rsal motor vagal nucleus is descriL-cd aft(r ir .l~.,:tioes of hortet'~is:', peroxidas¢ in ~,ariou~ parts of the c :rebellar cortex and nucle=, l'he projection is scanty, but • top6c~ ~'rlm4~mem is indicated: the rostr=d -,,art of the dorsal motor vagal nucleus Jpl~car ~. to project nufinly to the cortex of the posterior lobe, the caudal part mainly to the cortex of (i:e ~.tterior lobe, ~ d the fibres ~vpeu to reich ah,o the f a s t i i ~ and anterior interposit.e nuclei.
A cerebellar afferent projection from the dorsal motor vagal nucleu.~ (NDX) has previously been mentioned by Kotchabhakdi and Walberg [9[ in the cat a;~d by Chan-Palay [1] in the monkey. However, this projection has so far not been studie: systematically. We deemed it of interest therefore to map the distributi,>n of rctrogrlLdely labelled cells in N D X in our large material of cat,: injectcct with horseradish peroxidase (HRP) in the cerebellum. /tJt~ 70 ¢~ts were used for this study. They had been injected with peroxidue ( S i p u or Scrval) in all cerebellar cortical lobuh:s and the cerebellar nuclei. Most cases have been used in previous studies from our laboratory, and the kxalization and extent of the injection si~es have been illustr,".ted in ~ reports (see especially refs. 3, 4, 5, 10 and 15). The operations were ,~erformed under Nembutal or Mebumal anaesthesia, and various amounts of HRP were delivered either by pressure injections through a Hamilton syringe or by iontclphoreti¢~ ejection= th;oujh 8Jas~ pipettes. Table I gives the weight, concen:ration of HRP injected, amount/ej~-tion time and survival time for the 14 positive czses.
• On leave from the Shan~ai i k t i n Research Institute, Academia Simca, Shanghai, C.:hir a, ,j,,d,: yt~:. Fellenr~p Prolp'am of .,e Nm'wet~m Agency for lnternatior, al Development (NORAD).
"To ~ u m ~ p o m ~ e should be a.a.dressed. $Twocats werei n ~ wi~. ~ctin (Sigma peroxidasetyve Vi labelled wheat germ agglutinin). Tt'c : in wu'¢ dtu~ed in Iobulus f~mple~ =nd the anterior lobe. O'JIO4-]I~I01B2/0000--.{H~/$ 02.75 © 1982 Elsevier Scientific Publishers Ireland Ltd.
114
TABLE I SUMMARY OF EXPERIMENTAL DATA
The number, weight and survival ",umes. for all positive cases; the type, concentration and injected amount/current and ejection time for the HRP and the activation procedure u.ued. P., pressure injection. 1., ion¢ophorctic ejection. Cat B.St.L.
Weight {kg)
HRP Type
Conc.
619 649 665 689 692 699 717 225 762 772 826 919 °67 968
2.1 2.7 3.0 1.8 1.8 2.0 2.8 4.0 2.5 2.5 2.0 2.7 2.4 2.3
Sigma Sigma Signm Signm Sigma Sigma Signm Sigma Sigma Serva Serva Servaa Lectin Lectin
50% w/v 75% w/v Y~)%w/v 50% w/v 50% w/v 50% w/v 5 0 ~ w/v 50% w/v 50eTew/v 5 0 ~ w/v 2 5 ~ w/v 4~t w/v 2% w/v 2% w/v
Injection/ejection
A~ivat~on
Survival ~,rne(da~)
P. 0 5 / d P. 0.3 p.1 P. 0.5 #1 Po 0.4 ~1 P. 0.4 ~1 P. 0.3/tl P. 0.15 pl P. 0.2/d P. 0.3 td P. 0.1 p.I P. 0.2/d I. 5 ~ , 2 x 5 rain P. 2 × 0.2 ~tl P. 2 x 0.2 141
DAB DAB DAB DAB DAB DAB DAB DAB DAB DAB TMB TMB TMB TMB
3 ! 2 1 2 2 2 2 1 2 2 2 2
aln cat B.SI.L. 919 poly-L-ornithine 50 I,;tml [7] was added to the HRP.
After a ~urvival time usually varying Crom I to 3 days, the cats were killed under deep Nembutal or Mebumal anaesthesia by intracardiac I~rfusion either with 0.4~/e formaldehyde and 1.25e/o glutaraldehyde in phosphate buffer, or with 0 . 1 ~ phosphate buffer at pH 7.4 or physiological saline, foflowed by 1.25~'e glutaraidehyde and l~s paraformaldehyde in phosphate buffer, and fin~ly with 1007o sucrose. The brainstem and the cerebellum were isolated and removed. The brainstem was cut transver~ly and tile cerebellum sagittally or frontall~ in serial sections at 50 ~J~. Two out of 5 con~,ecutive sections were selected and li'Jounted. They were treated :ither with diaminobenzidine (DAB) as described by Grab,am ~td Karnovsky [6] or with tetramethyIbenzidine (TMB) according to Mesu!am [12]. One series was weakly stained with cresyl violet, thionin or neutral red. The presence of retrogradely labelled neurons in NDX was studied with bright- and dark-field, and interference contrast microscopy. The sections from the positive cases were drawn in a projection apparatus. 'To enable comparison among the differer.t ~:ases, the findings were later carefully transferred to a standard diagram of 5 equidistantsections through NDX (see Fig. 2). As mentioned above, retrogradely stained cells in NDX were found in only 14 cats, and only in 3 of these animals (B.St.L. 665, 762 and 826) were raore than one positive cell found in each. The cells were of varying intensity, The toted stained ~area
115 ro.~t r a l ~,,
5.
NOX
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76:
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Fig. 1. (Left). Diagram of the surface of the feline cerebellum [I l] showing the extent o¢ the corti¢¢;', ~:aining in 12 of our positive cases. Fig. 2. (Right). Diagram of 5 equidistant sections through the NDX giving the distribution aad size of all positive neuroncs (on the left) and the suggested topical organization for the cerebeilar projection (or) the right). Squares represent large cells, circles represent medium-sized neu~on~.~) a,d (ria.,~glcs indicate small cells. Areas projecting to the cerebellar anterior lobe are marked by vertical line,., those projecting to the posterior lobe by horizontal lines. Abbreviations: c.c., central canal; i.e., nucl-.us intercalatus; N.c., nucleus commissuralis of Cajal; NDX, dorsal motor vagal nucleus; N.g., graci]e nucleus; N.t.s., nucleus of the solitary tract; N.V.M., medial vestibular nucleus; P.h., nucleus praepositus hypoglossi; XII, motor nucleus of cranial nerve XII.
of t~cortical injection site ~n 12 of the positive cases is illustrated in Fig. ~ :, the rcmainingltWo positive cases were injected in the fastigial and anterior imerpo.,;ite nuclei, r ~ ~ i v e l $ , A total nun,bar of 18 labelled neurones were observed. Si):t¢i,en o f t h ~ occuffed after ¢ortlc~d inject,ions, All except two of the retrogradely labdied neuroncs were t,Ound i n t h e urstamed series. No rctrogradely stained cells were found in NDX after injections in crus I and II, the posterior imerposite or der,,~.ate *The staining of theinj~'tion dt¢ in our 12 positive conical, injections was in most cases restricted t', l:he molecular and granular layers and the fvli.al white matter. A few cats showed in addition a slight staining of the central cercbellar white matter, rut the cerebellar peduncles or central nuclei were not i,~volved by the staining in any of these cases.
li6
nuclei. It shouM also be stressed that many cats injected in the ~ e a r ¢ ~ as the positive animats showed no labelted neurones. Neither differcmces in the amount of the injected H I ~ , nor the different sensitivities of the two activation procedures used, can explain our negative cases or the varying intensity of staining. Negative observations were made both in the DAB and the T M B activated series, and our 3 cats with more than one cell showed faintly as web as intensely labelled neurones. One possible explanation may be that the cerebellar fibres are collaterals from other NDX efferents, and that uptake and retrograde transport of H R P in these collaterals are only sufficient under optimal conditions to visualize t~_. parent cell bodies. This ~ a y also be the explanation why some neurones were only faintly labelled, while others showed a more intense staining. The distribution of labelled cells in NDX after cerebellar injections is shown in Fig. 2. The projection is bilateral, but in the figure all cells have been transferred to the left side. The projecting neurones are of different sizes (Fig. 3), but most neurons are large (with a maximum diameter exceeding 25 ~m) or medium sized ewith a maximum d~ameter between 15 and 25 /~m). Our material suggests the presence of a ,~opical arrangement within t'-,e projection: after injections in the anterior cerebellar lobe 7 out of the 9 labelled neurones were situated in the caudal half of NDX~ and after posterior lobe injections 6 cells out of 7 were found in its : ,::~'~tralhalt" (Fig. 2). A similar distribution was found fcr the cells in the nucleus of ~ solitary tract projecting onto the cerebellum [17]. Furthermore, our findings in~i~:ate a mediolateral distribution, so that vermal regions (both in the anterior and ~he posterior lobe) receive input from the medial NDX, while lateral cerebellar regions re,:e;,vc fibres from the lateral NDX, but our material is not conclusive on this point. This differential distribution is interesting since i.a. a topical organization has been indicated also for the NDX effe~'ems to the gastrointestinal tract; its rostral part receives fibres from the medial NDX and its caudal portion is innervated from the lateral NDX [16, 22].
Fig. 3.a: photomicrograph from the left NDX in cat B.St.L. 717, showing a retrogradely labelled large n.-urone (DAB reaction). Scale ',0 #m. b: photumicrograph from t[~e right NDX in cat B.St.L. ~26, ,howitlg ~ retrogradely labelled small neurone (TMB reaction). Same scfl¢ as a. c: photomicrograph fr¢,m the left NDX in cat B.StiL. 919, showing a reu'ogradety labeU~d . . . . . . . . " ........... aia.
117
Recent studies using retrograde and anterograde tracer techniques (see e.g° r.ffs. 2, 8, 14, !6, 18-22) have extended our knowledge concerning the origin and distribution of the N D X efferent fibres of the ',agus nerve described in previous studies where degeneration techniques were used (for references to these studies, and for a historical survey, see ref. 13). However, in none of these studies was the connection observed here mentioned. The demonstration of a cerebellar input trom the N D X adds further evidence to the concept that the cerebellum is involved in activities related to visceral functions. l Chan-Palay, V., Cerebellar Dentate Nucleus: Organization, Cytology and Transmitters, Spritlger,
Berlin, i977. 2 Contreras, R., Gomez, M. and Norgren, R., Central origins of cran!a2 nerve parasympa: hetic neurons in the rat, J. comp. Neurol., 190 (1980) 373-394. 3 Dietrichs, E., The cerebellar corticonuclear and nucleocortical pre~.eetions in the cat a:~ studied ~,ith anterograde and retrograde transpen of horsera6ish peroxidase, III. The anterior lobe, Anat. Embryol., 162 (1981) 223-2A7. 4 Dietrichs, E. and Walberg, F., The cerebellar co~iconuclear and micleocortical projections in the cat as studied with anterograde and retrograde transport of horseradish peroxidase, I. The paramedian lobule, Anat. Embryol., 158 (1979) 13-39. 5 Dietrichs, E. and Walberg, F., The cerebellar co~.iconuclear ard nucleocortical projections in the cat as studied with anterograde anti retrograde transport of horseradish peroxidase, II. Lobulus simple~, crus I and I1, Anat. Embryol. 161 (1980) 83-103. 6 Gr;iham, R.C. and Karnovsky, M.J.. The early stag.-s of absorption of injected horseradish peroxidase in the proximal tubule o:? movie kidney: ultrastructural cytochemistry by a new technique, J. Hintoehem. Cytochem., 14 (1966) 291-302. 7 Itaya, S.K., Williams, T.H. and Engel, E.L., Anlerograde transport of horseradish peroxidase enhanced by poly-L-ornithine, Brain Res., 150 (1978) 170- 176o 8 Karim, M.A. and Leong, S.K., Neurons of origin of cervical vagus nerves in the rat and monkey, Brain Res., 186 (1980) 208-2!0. 9 Kotchabhakdi, N. and Walberg, F., Cerebellar afferents from neurons in motor nuclei of cranial nerves demonstrated by retrograde axonal transport of horseradish "Jeroxidase, Brain Res., 137 (1977) 158-163. 10 Kotchabhakdi, N., Hoddevik, G.H. and Walberg, F., CerebeUar afferent projections from the perihypoglossal nuclei: an experimental study with the method of retrograde axonal transport of horseradish peroxidase, Exp. Brain Res., 31 (1978) 13-29. 11 Larsell, O., The Comparative Anatomy and Histology of the Cerebellum from Monotremes through Apes, J. J ',asen (Ed.), The University of Minnesota Press, Minneapolis, 1970. 12 Mesulam, M.-M., Tetramethyi benzidine for horse::adish perox~dase neurohistochemistry: a noncarcinogenic blue reaction-product with superior sensiti,/i,y for visualizing neural afferents and efferents, J. H, stoehem. Cytochem., 26 (1978) 106-! 17. 13 Mitchell, G.A.G. and Warwick, R., The dor.~al vagal nucleus, Acta anat., 25 (1955) 371-395. 14 Nosaka, S., Yamamoto, T. and Yasur~aga, K., Localization of vagal cardioinhibitory preganglionic neurons within rat brain stem, J. comp. Neurol., 186 (197';) 79-92. 15 Pierce, E.T., Hoddevik, G.H. and Walberg, F., The cerebellar projection from the raphe nuclei ~t~ the cat as studied with the method of retrograde transport of horseradish peroxidase, Anat Embryol. 152 (I977) 73-87. 16 Satomi, H., Yamamoto, T., lse, H. and Takatama, H., Origins of the parasympathe~.ic preganglior.~:c fibers to the cat intestine as demonstrated by the horseradish p~.-roxidase method, Brain Res., 15t (1978) 571-578.
il8 17 So.tuuut, R. and W~bctlg. F., ~ &fferzaa from the ma:lgm of dig saf:,aO trma. Neago0ci. L~.t., I I (19799 41--47. 18 Stt~.s~, S.L., (X'igi~ of cardi~ v ~ l l l 1 ~ ~" ar ¢ ~ trmugg~ gudy, Braa ~ . ,
236 (1982) 15-25. 19 Sugimo¢o. T., Ito~t, g.. Mtmeo, N., Iqomum, S. md ~ A., Tlw 01heo( orlgla o( car¢lii~ pwla~l~m¢ flt~s ~ ~ ~ ~ m ~-IltP run,jr ~,, me cat, ~ . l ~ t . , 12 (1919) 53-~1L 20 Su:tivan. J..~. ~KI ~ , N.A.. An ~'.bolrmle l a l ~ h l ~ o( autos o( dm derml motor nu,:igus of tlx ~ to rat ~ ~ at ¢llemtmsutz~ by i ~ , .AgUt muzL, ltO (1981) I ?.Jt- 133. ~1 "lodo, K., ¥Jmmmmo, T., Sstomi, H., I~, H., T ~ , H. ~ T~rsluisM, K., ~ of pr~ic fibers to the smo..mr~ sad s u l o - ~ a e ~ r~iom ha tl~ cat I ~ f l is audied by the ~ peroxida~ mobod, Braia lies., 130 (197'7) $45--.~i0. 22 Ym'namoto, T., Sslomi, H.. I~, H. m~l Tsi,sluu~, K., E videace o( dw d~J immrv~cm of Ibe ~ stomach by the va4ptl dcq14t] molo¢" mid ~ ~ t a d ~ as damotzl~'-~ed by the peroxidase method. Br~n Res.. 122 (1977) 123-131.
Letter~, 32 (1982) 113-118 .Scientific Publishers Ireland Ltd.
I13
CEREilELLAR AFFERENT FIBRES FROM THE DORSAL MOTOR VAGAL NUCLEUS IN THE CAT
ZF,-.HUI Z H E N G ' , ESPEN DIETRICHS*" and FRED WALBERG
A~Comi¢~ Institute, Umve~ly of Oslo, Karl Johans&t. 47, Oslo ! (Norway) (Reoeivcd June 24th, 19~2; Revised version received July 5th. 1982; Accepted Jul, 10th, 1982)
Key words: dorsal motor vagal nucleus - cerebellum - retrograde transport
A biLtteral cere~ll~r afferent projection from the d.)rsal motor vagal nucleus is descriL-cd aft(r ir .l~.,:tioes of hortet'~is:', peroxidas¢ in ~,ariou~ parts of the c :rebellar cortex and nucle=, l'he projection is scanty, but • top6c~ ~'rlm4~mem is indicated: the rostr=d -,,art of the dorsal motor vagal nucleus Jpl~car ~. to project nufinly to the cortex of the posterior lobe, the caudal part mainly to the cortex of (i:e ~.tterior lobe, ~ d the fibres ~vpeu to reich ah,o the f a s t i i ~ and anterior interposit.e nuclei.
A cerebellar afferent projection from the dorsal motor vagal nucleu.~ (NDX) has previously been mentioned by Kotchabhakdi and Walberg [9[ in the cat a;~d by Chan-Palay [1] in the monkey. However, this projection has so far not been studie: systematically. We deemed it of interest therefore to map the distributi,>n of rctrogrlLdely labelled cells in N D X in our large material of cat,: injectcct with horseradish peroxidase (HRP) in the cerebellum. /tJt~ 70 ¢~ts were used for this study. They had been injected with peroxidue ( S i p u or Scrval) in all cerebellar cortical lobuh:s and the cerebellar nuclei. Most cases have been used in previous studies from our laboratory, and the kxalization and extent of the injection si~es have been illustr,".ted in ~ reports (see especially refs. 3, 4, 5, 10 and 15). The operations were ,~erformed under Nembutal or Mebumal anaesthesia, and various amounts of HRP were delivered either by pressure injections through a Hamilton syringe or by iontclphoreti¢~ ejection= th;oujh 8Jas~ pipettes. Table I gives the weight, concen:ration of HRP injected, amount/ej~-tion time and survival time for the 14 positive czses.
• On leave from the Shan~ai i k t i n Research Institute, Academia Simca, Shanghai, C.:hir a, ,j,,d,: yt~:. Fellenr~p Prolp'am of .,e Nm'wet~m Agency for lnternatior, al Development (NORAD).
"To ~ u m ~ p o m ~ e should be a.a.dressed. $Twocats werei n ~ wi~. ~ctin (Sigma peroxidasetyve Vi labelled wheat germ agglutinin). Tt'c : in wu'¢ dtu~ed in Iobulus f~mple~ =nd the anterior lobe. O'JIO4-]I~I01B2/0000--.{H~/$ 02.75 © 1982 Elsevier Scientific Publishers Ireland Ltd.
114
TABLE I SUMMARY OF EXPERIMENTAL DATA
The number, weight and survival ",umes. for all positive cases; the type, concentration and injected amount/current and ejection time for the HRP and the activation procedure u.ued. P., pressure injection. 1., ion¢ophorctic ejection. Cat B.St.L.
Weight {kg)
HRP Type
Conc.
619 649 665 689 692 699 717 225 762 772 826 919 °67 968
2.1 2.7 3.0 1.8 1.8 2.0 2.8 4.0 2.5 2.5 2.0 2.7 2.4 2.3
Sigma Sigma Signm Signm Sigma Sigma Signm Sigma Sigma Serva Serva Servaa Lectin Lectin
50% w/v 75% w/v Y~)%w/v 50% w/v 50% w/v 50% w/v 5 0 ~ w/v 50% w/v 50eTew/v 5 0 ~ w/v 2 5 ~ w/v 4~t w/v 2% w/v 2% w/v
Injection/ejection
A~ivat~on
Survival ~,rne(da~)
P. 0 5 / d P. 0.3 p.1 P. 0.5 #1 Po 0.4 ~1 P. 0.4 ~1 P. 0.3/tl P. 0.15 pl P. 0.2/d P. 0.3 td P. 0.1 p.I P. 0.2/d I. 5 ~ , 2 x 5 rain P. 2 × 0.2 ~tl P. 2 x 0.2 141
DAB DAB DAB DAB DAB DAB DAB DAB DAB DAB TMB TMB TMB TMB
3 ! 2 1 2 2 2 2 1 2 2 2 2
aln cat B.SI.L. 919 poly-L-ornithine 50 I,;tml [7] was added to the HRP.
After a ~urvival time usually varying Crom I to 3 days, the cats were killed under deep Nembutal or Mebumal anaesthesia by intracardiac I~rfusion either with 0.4~/e formaldehyde and 1.25e/o glutaraldehyde in phosphate buffer, or with 0 . 1 ~ phosphate buffer at pH 7.4 or physiological saline, foflowed by 1.25~'e glutaraidehyde and l~s paraformaldehyde in phosphate buffer, and fin~ly with 1007o sucrose. The brainstem and the cerebellum were isolated and removed. The brainstem was cut transver~ly and tile cerebellum sagittally or frontall~ in serial sections at 50 ~J~. Two out of 5 con~,ecutive sections were selected and li'Jounted. They were treated :ither with diaminobenzidine (DAB) as described by Grab,am ~td Karnovsky [6] or with tetramethyIbenzidine (TMB) according to Mesu!am [12]. One series was weakly stained with cresyl violet, thionin or neutral red. The presence of retrogradely labelled neurons in NDX was studied with bright- and dark-field, and interference contrast microscopy. The sections from the positive cases were drawn in a projection apparatus. 'To enable comparison among the differer.t ~:ases, the findings were later carefully transferred to a standard diagram of 5 equidistantsections through NDX (see Fig. 2). As mentioned above, retrogradely stained cells in NDX were found in only 14 cats, and only in 3 of these animals (B.St.L. 665, 762 and 826) were raore than one positive cell found in each. The cells were of varying intensity, The toted stained ~area
115 ro.~t r a l ~,,
5.
NOX
~J;Xn/
"~./
L._
)\
> I
,19R
2 ~<'~-
76:
-
~
"'
-
1
" ....
.... 3
619
~j-
~ /
692
.
C~ udQl
Fig. 1. (Left). Diagram of the surface of the feline cerebellum [I l] showing the extent o¢ the corti¢¢;', ~:aining in 12 of our positive cases. Fig. 2. (Right). Diagram of 5 equidistant sections through the NDX giving the distribution aad size of all positive neuroncs (on the left) and the suggested topical organization for the cerebeilar projection (or) the right). Squares represent large cells, circles represent medium-sized neu~on~.~) a,d (ria.,~glcs indicate small cells. Areas projecting to the cerebellar anterior lobe are marked by vertical line,., those projecting to the posterior lobe by horizontal lines. Abbreviations: c.c., central canal; i.e., nucl-.us intercalatus; N.c., nucleus commissuralis of Cajal; NDX, dorsal motor vagal nucleus; N.g., graci]e nucleus; N.t.s., nucleus of the solitary tract; N.V.M., medial vestibular nucleus; P.h., nucleus praepositus hypoglossi; XII, motor nucleus of cranial nerve XII.
of t~cortical injection site ~n 12 of the positive cases is illustrated in Fig. ~ :, the rcmainingltWo positive cases were injected in the fastigial and anterior imerpo.,;ite nuclei, r ~ ~ i v e l $ , A total nun,bar of 18 labelled neurones were observed. Si):t¢i,en o f t h ~ occuffed after ¢ortlc~d inject,ions, All except two of the retrogradely labdied neuroncs were t,Ound i n t h e urstamed series. No rctrogradely stained cells were found in NDX after injections in crus I and II, the posterior imerposite or der,,~.ate *The staining of theinj~'tion dt¢ in our 12 positive conical, injections was in most cases restricted t', l:he molecular and granular layers and the fvli.al white matter. A few cats showed in addition a slight staining of the central cercbellar white matter, rut the cerebellar peduncles or central nuclei were not i,~volved by the staining in any of these cases.
li6
nuclei. It shouM also be stressed that many cats injected in the ~ e a r ¢ ~ as the positive animats showed no labelted neurones. Neither differcmces in the amount of the injected H I ~ , nor the different sensitivities of the two activation procedures used, can explain our negative cases or the varying intensity of staining. Negative observations were made both in the DAB and the T M B activated series, and our 3 cats with more than one cell showed faintly as web as intensely labelled neurones. One possible explanation may be that the cerebellar fibres are collaterals from other NDX efferents, and that uptake and retrograde transport of H R P in these collaterals are only sufficient under optimal conditions to visualize t~_. parent cell bodies. This ~ a y also be the explanation why some neurones were only faintly labelled, while others showed a more intense staining. The distribution of labelled cells in NDX after cerebellar injections is shown in Fig. 2. The projection is bilateral, but in the figure all cells have been transferred to the left side. The projecting neurones are of different sizes (Fig. 3), but most neurons are large (with a maximum diameter exceeding 25 ~m) or medium sized ewith a maximum d~ameter between 15 and 25 /~m). Our material suggests the presence of a ,~opical arrangement within t'-,e projection: after injections in the anterior cerebellar lobe 7 out of the 9 labelled neurones were situated in the caudal half of NDX~ and after posterior lobe injections 6 cells out of 7 were found in its : ,::~'~tralhalt" (Fig. 2). A similar distribution was found fcr the cells in the nucleus of ~ solitary tract projecting onto the cerebellum [17]. Furthermore, our findings in~i~:ate a mediolateral distribution, so that vermal regions (both in the anterior and ~he posterior lobe) receive input from the medial NDX, while lateral cerebellar regions re,:e;,vc fibres from the lateral NDX, but our material is not conclusive on this point. This differential distribution is interesting since i.a. a topical organization has been indicated also for the NDX effe~'ems to the gastrointestinal tract; its rostral part receives fibres from the medial NDX and its caudal portion is innervated from the lateral NDX [16, 22].
Fig. 3.a: photomicrograph from the left NDX in cat B.St.L. 717, showing a retrogradely labelled large n.-urone (DAB reaction). Scale ',0 #m. b: photumicrograph from t[~e right NDX in cat B.St.L. ~26, ,howitlg ~ retrogradely labelled small neurone (TMB reaction). Same scfl¢ as a. c: photomicrograph fr¢,m the left NDX in cat B.StiL. 919, showing a reu'ogradety labeU~d . . . . . . . . " ........... aia.
117
Recent studies using retrograde and anterograde tracer techniques (see e.g° r.ffs. 2, 8, 14, !6, 18-22) have extended our knowledge concerning the origin and distribution of the N D X efferent fibres of the ',agus nerve described in previous studies where degeneration techniques were used (for references to these studies, and for a historical survey, see ref. 13). However, in none of these studies was the connection observed here mentioned. The demonstration of a cerebellar input trom the N D X adds further evidence to the concept that the cerebellum is involved in activities related to visceral functions. l Chan-Palay, V., Cerebellar Dentate Nucleus: Organization, Cytology and Transmitters, Spritlger,
Berlin, i977. 2 Contreras, R., Gomez, M. and Norgren, R., Central origins of cran!a2 nerve parasympa: hetic neurons in the rat, J. comp. Neurol., 190 (1980) 373-394. 3 Dietrichs, E., The cerebellar corticonuclear and nucleocortical pre~.eetions in the cat a:~ studied ~,ith anterograde and retrograde transpen of horsera6ish peroxidase, III. The anterior lobe, Anat. Embryol., 162 (1981) 223-2A7. 4 Dietrichs, E. and Walberg, F., The cerebellar co~iconuclear and micleocortical projections in the cat as studied with anterograde and retrograde transport of horseradish peroxidase, I. The paramedian lobule, Anat. Embryol., 158 (1979) 13-39. 5 Dietrichs, E. and Walberg, F., The cerebellar co~.iconuclear ard nucleocortical projections in the cat as studied with anterograde anti retrograde transport of horseradish peroxidase, II. Lobulus simple~, crus I and I1, Anat. Embryol. 161 (1980) 83-103. 6 Gr;iham, R.C. and Karnovsky, M.J.. The early stag.-s of absorption of injected horseradish peroxidase in the proximal tubule o:? movie kidney: ultrastructural cytochemistry by a new technique, J. Hintoehem. Cytochem., 14 (1966) 291-302. 7 Itaya, S.K., Williams, T.H. and Engel, E.L., Anlerograde transport of horseradish peroxidase enhanced by poly-L-ornithine, Brain Res., 150 (1978) 170- 176o 8 Karim, M.A. and Leong, S.K., Neurons of origin of cervical vagus nerves in the rat and monkey, Brain Res., 186 (1980) 208-2!0. 9 Kotchabhakdi, N. and Walberg, F., Cerebellar afferents from neurons in motor nuclei of cranial nerves demonstrated by retrograde axonal transport of horseradish "Jeroxidase, Brain Res., 137 (1977) 158-163. 10 Kotchabhakdi, N., Hoddevik, G.H. and Walberg, F., CerebeUar afferent projections from the perihypoglossal nuclei: an experimental study with the method of retrograde axonal transport of horseradish peroxidase, Exp. Brain Res., 31 (1978) 13-29. 11 Larsell, O., The Comparative Anatomy and Histology of the Cerebellum from Monotremes through Apes, J. J ',asen (Ed.), The University of Minnesota Press, Minneapolis, 1970. 12 Mesulam, M.-M., Tetramethyi benzidine for horse::adish perox~dase neurohistochemistry: a noncarcinogenic blue reaction-product with superior sensiti,/i,y for visualizing neural afferents and efferents, J. H, stoehem. Cytochem., 26 (1978) 106-! 17. 13 Mitchell, G.A.G. and Warwick, R., The dor.~al vagal nucleus, Acta anat., 25 (1955) 371-395. 14 Nosaka, S., Yamamoto, T. and Yasur~aga, K., Localization of vagal cardioinhibitory preganglionic neurons within rat brain stem, J. comp. Neurol., 186 (197';) 79-92. 15 Pierce, E.T., Hoddevik, G.H. and Walberg, F., The cerebellar projection from the raphe nuclei ~t~ the cat as studied with the method of retrograde transport of horseradish peroxidase, Anat Embryol. 152 (I977) 73-87. 16 Satomi, H., Yamamoto, T., lse, H. and Takatama, H., Origins of the parasympathe~.ic preganglior.~:c fibers to the cat intestine as demonstrated by the horseradish p~.-roxidase method, Brain Res., 15t (1978) 571-578.
il8 17 So.tuuut, R. and W~bctlg. F., ~ &fferzaa from the ma:lgm of dig saf:,aO trma. Neago0ci. L~.t., I I (19799 41--47. 18 Stt~.s~, S.L., (X'igi~ of cardi~ v ~ l l l 1 ~ ~" ar ¢ ~ trmugg~ gudy, Braa ~ . ,
236 (1982) 15-25. 19 Sugimo¢o. T., Ito~t, g.. Mtmeo, N., Iqomum, S. md ~ A., Tlw 01heo( orlgla o( car¢lii~ pwla~l~m¢ flt~s ~ ~ ~ ~ m ~-IltP run,jr ~,, me cat, ~ . l ~ t . , 12 (1919) 53-~1L 20 Su:tivan. J..~. ~KI ~ , N.A.. An ~'.bolrmle l a l ~ h l ~ o( autos o( dm derml motor nu,:igus of tlx ~ to rat ~ ~ at ¢llemtmsutz~ by i ~ , .AgUt muzL, ltO (1981) I ?.Jt- 133. ~1 "lodo, K., ¥Jmmmmo, T., Sstomi, H., I~, H., T ~ , H. ~ T~rsluisM, K., ~ of pr~ic fibers to the smo..mr~ sad s u l o - ~ a e ~ r~iom ha tl~ cat I ~ f l is audied by the ~ peroxida~ mobod, Braia lies., 130 (197'7) $45--.~i0. 22 Ym'namoto, T., Sslomi, H.. I~, H. m~l Tsi,sluu~, K., E videace o( dw d~J immrv~cm of Ibe ~ stomach by the va4ptl dcq14t] molo¢" mid ~ ~ t a d ~ as damotzl~'-~ed by the peroxidase method. Br~n Res.. 122 (1977) 123-131.