Test results presented indicate that 30-day hypokinesia did not affect the intensity of nystagmus: velocity of slow phase, total number of jerks, and duration of the reaction in animals were the same as before mobility restriction and did not differ from those of the control group. However, hypokinesia resulted in the disappearance of habituation of the vestibulary system to repeated angular accelerations. The known hypokinetic changes in the endocrine system were studied. It was concluded that reduction in adrenergic function may be the cause of disappearance of vestibular apparatus habituation during hypokinesia

Gorgiladze, G. I.

Kazanskaya, G. S.

English

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NASA 'I'7CSIt`fICAL ME1N^t^ADIIX,'M	 NASA TM-75995
I!QFIdJEIJCE OF N17BII iZ'Y RFSTf2ICTI0N ON HAIiI'I'tTATION OF ^ VESTIIi1JIAR APPAl2ATiJS
G. I. (^rgiladze and G. S. Kazanskaya
Trans]<-+tion of "Vliyaniye ogranicheniya podvizhnusti na privykaniye
vestibulyarrxxp apparata," Dokl a`d Akademii Nauk SSSR,
Vol. 211, No. 4, 1 Aug 1^ 05-10 8.
(NASA-TM-75995)	 INPLi1ENCE OF "10IIILITY
	
Yn^-17669
RI?STRICTI(`N ON HAIIITUATInN OF THE VESTIBULAR
APPA:tATUS (National Aeronautic.; an^1 Space
Administration} 8 p hC A02/"+F A01 CSCL O^iC	 Unclas
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NATIONAL AERlJNALlI'ICS ?^'QD SPACE ADMINISTRATION
WASI;INO'i^GV, D. C. 20546
	
FF^3RL^RY 1980
INFIIJET0.1E OF' NrJF3ILITY RESTRICTION ON HAI3IT[JATION OF TES VESTIBULAR APPARATUS
G. I. Gorgiladze and G. S. Kazanskaya
Institute of Bic^nedical Probler•s, Moscow
Recently specialists in space medicine hav= shown great interest in a coi^re- /1005*
herisive study of hypokinesia as one of the factors in space flight. Prolonged re-
striction of mobility causes disruptions in the activities of various functional
systems: cardiovascular (3,15] , respiration [10] , support-nusc ►11.^+^ (1,11,13) , blood
[5, 18J, metabolic [14]. Ciypokinesia affects tine bioelectric activity of the grain
(6,13] arxi human psychic functions (2,11].
The vestibular function likewise undergoes definite changes taking the form of
deterioration in tolerance of angular and rectilinear acceleration [17,19]. Fiow^ever
the bedrest method of hypokinesia, aside from the actual rPStriction of rrotor activi-
ty, also alters the direction of gravity in respect to the longitudinal axis of the
body (the so-called orthostatic factor), which by its very nature may prove to be
the cause of many disorders. This situation may be avoided in experiments with lab-
oratory animals where the horizontal orientation of the body does rot really change
when they are placc^i in hypokinetic cages.
The most important feature in the study of the vestibular function under hypo-
kinetic conditions appeared to be an investigation of the reactivity of the vestibu-
lar apparatus to repeated angular acceleration or the so-called habituation phP^-
non, a process which is bayed upon vestibular training.
The exp .^ximents were conducted on 16 vigorous adult rabbits of both sexes weigh-
ing 3.0-3.5 kg. They were divided into two groups of eight. Animals in the experi-
r^^ental group were kept in hy;^okinesia for 30 days, achieved by placing them in spe-
cial cages that severely restricted mohility [£3]. The controls wore kept ir. ordina-
ry vivarium conditions. Nyst3gmus was irriuced by the action of negative angular ac-
celeration 40°/sec produced by a platform revolving at 360 °/sec located on the axis
of a TSLS-3 laboratory centrifuge. Previous tc the experiment the animals were e-
q^iipped with a special costume and placed on the revol^ •inq platform of the centrifuge.
Ntunbers in the margin indicate pagination in the foreign text.
1
The horizontal semicircular canals were situated in the optimal stimulation position
(head affixed at the piwtal canter at an angle of 40-45° to the horizontal plane).
To eliminate sight during rotation the animals were blindfolded.
The experiment pattern was as follows: at first the animals were subjected t;o
a single counterclockwise rotation (pretest to the left). Then there w p..r+e ^0 clock-
wise rotations at 5 minute intervals fol.low^xi by a single eounterclocJcwise rotation
(posttest to the left). Clockwise rotations 1 and 20 were designated respectively
as clockwise Pre- and pastt^Gts. The animals of the e^erimental _group w^-se subject-
ed to a similar effec^ • at the end of 30-day hypokinesia.
For recording elects^onystagmograms /1006
we sewed into the oorn.^s of one eye elec-
trodes in the forn^ of :,ilverplated multi-
strand wires with fluoroplastic insulation,
the other ends applied to the skull
subcutaneously and soldered to a nolyrod
connection. This was attached to the skull
with styroclear. The electronystagmngram
was made on an F1em^-SCh^Snalx3er mingograph •
with a time constant of 2.5-5 sec. At the
same time a reinforced signal was fed into
an ST'^R-41 recorder (Nihon Cobden) and re-
corded by means of a Pt4-1 block with a
transnussion band of 0-60 Hz. Quantitative
processing of the electronystacurocrram was
done with magnetic tape on a central elec-
^^I^^il^lpl,L,l;dll^,^^^III',iVl!;,Ill^lh^l^ii^llii^l ,^
	
tI L^:«•^
^n^'I^,v^:, l l'^t ^ 'I ^ . ,^ j^rl'p^^^'4 I^lill^
I
^..^^41^^11	 ^IIII^^!'^^,^;'",
	 ^'ll,^lll^^hil,ll^ll^^l1
Ur-^^1 I11 ^hlll Ihlll lrlrjr ^ i l^1 ^•••^^
, I I ^^^
^^Iliilil^ i ^ ;
^^'^i
	 I,	 J
-^^
Fig. 1. Nystagmic reaction in rabbits
of control group. 1, 7 - nystagmus :^t
counterclockwise pre- anti posttests.
2 to 6 - nystagmus at clockwise tests
#1, 5, 10, 15, 20. Heavy straight line
at bottom -duration of anclular acce-
leration. Calibration: 1 sec, 100 mn^
tropic conputer ^'1-220 A follaainq a s•,^
dally designed program. These electronystagmograF^hic parameters were considered:
total number of nystagmic jerks, length of al.l reactions, average frequency, ampli-
tude, length and sF^eed of fast and slow nystagmic phases (in microvolts/seci.
Control Study. v]ith repeated rotation in one direction the nystagmic reaction of the
eyes shows chang:s in all indices. Front one revoluticn to the ne.^ct there is a gradu-
al decrease in '.:he average values of sF^eeci of the slaw phase of nystacmais, anplit^xie,
2
^rw...
	 :i' Ali ^ f1r^ il^^'^ 111 !1^'^^ , y 1:Mi^^i ,• ^,•^.': d'^^^ .r
I'^	 "	 ^^^n Inh' ► ^ , ► h,^'illlli111^I`ti 	'h' ^,^
^w► I^'^^'II ►► I 
'^i''^'IT^ ^^^! I'^I1^r'^;^^,j i 	Mrr^^+WWV1
^	 ^I^^II^^I^^..,; . ^, 	 ^
J``^'ti^y' ^ ^ 11 I I I I tl l ^ l iil ^ I Iti^ i r^ v^1wv^,v^n^ww,JyrYlN,nr^r,^r,,,,...._
h^^l^llllt^l^ll ^^^+I^I'I'^Ihli^u^i
►►1^^^i^►►tip+--
J
6
Fig. 2. Vystaymic reaction of rabbits
to 31 days hypokinesia. 1-5 nystagmus
reaction to clockwise tests #1, S, 10,
15, 20. 6 -indication of platform ro-
tation speed. Calibration: 1 sec, 100
rticrowlts
frequency, total numbs of nystaaanie jPSks,
length of reaction (Fig. 1). These chan-
ges have an tu^dulatinq character.
Amonq the selected nystac^nic indices
those showing the Trost significant changes
are the speed of the slow phase and the
total numt^x of jerks. In respect to the
latter index the level of significance was
already unusually high at the 8th clock-
wise rotation test (P<0.01) and at the
20th (P X0.001) . Changes in average fre-
quency are less irxiicative. At the 12th
clocj.^aise test the level of significance
corresponds to the first threshold of re-
liability (P = 0.05), but on the 20th test
the difference was not reliable (P> 0.05) .
A cor^^r.ison of the counterclockwise pre-
and posttests likewise revealed a relia-
ble difference between them with the ex-
clu;ion of the average frequency (Table 1) .
ilypokinetic Anin^ls. During the first 3
clays following their being placed in mo-
bility-restricting cads the animals pre-
sented serious motor restlessness. They
usually calmed dawn on days 3-4. 'lbward
the enci of the experimental period the
rabbits lost weight, on the average 0.3-
0.4 kg (^-10$). Can day 31 they wpse tak-
en from the cages, dressed in the oosturm
and subjected to the rotational tests on
the schedule described above.
.!
0
`	 t
e
^c	 '
^	 ^	 ,o	 ,!—d	 b Karroo 4pea^t•ar —^
Fig. 3. Graphic renresP^tation of
change in total rn.unber of nyst^^^nic
jerks in norms 1 (1) and hypok inetic (2 )
rabbits r^eactinq to 20th clockwise re-
vc^lution with negative acceleration of
40°/sec. Arrows show counterclockwise
pre- and posttests for both groups of
animals. Graphy plotted on average
arithanetic values.
^:ey: a. Number of jerks.
b. Iotation numbers.
the scheriule described above.
Their nystac^nic reaction to the left and right rotation pretests w pxe practical-
ly the same as for the controls (Table 1). [lowever with repeated clockwise revolu-
3
TARLF. 1. EI^CT^[VYS'TA^1IC IT`IDICFS FhR CO[1I'F^I, (UPPER VAL^[lF5) Aim HYPOKINE-
TIC RAIIBIT`^ (LA'JER VAL^i.1FS) AT CQ1NI'FRC[^OCICWISE A'^1[) CI^OC^Q^IISE PRF- AND
POF'I'I'E,5'I'S :'ASID ON AVERAGE VALUE AN[^ LEVEI, OF SIC^TIFICANCE P
- - b	 Hpaxlrun. {n1w D,	 (^`	 Hpatry•uu^ tiv^,
a Il^a.n u,n •:m nn. ^.0 r.l ---- II -	 ---	 --	 --_
III„ • .r,^t {^11„rn^,-t I	 1'	 IIIYmY l ell^,^r.rt I	 1•
f
c^,14,,,,•,1,	 SI,•
 t.lP11111H4 •! •^ so r-ns !Ifs t-f^ ►+4 ^ o,(x ll ^
,d,an^	 a p•,rox
_IS3LIfs 24n5t1'.0 "^>0,'-
lhiuN'^ • 	ti,,:m^l,•t'nl„
q
ri'l,Ii 41, i i'!.SaS,R i Il,lrll
^•.t.yalx i i,fi X7,5 f.'i,R+7,7 X11,'!5
h	 II lul to I:I:IItO:ILlll/f I1. .`• ► .R L f .R I;i,3 F 1 ,^ < U,(All1 N • .Il;ullll
	 x	 c,^x '!7 ,u..',:1 _a,a^-.i >0,5
i	
4'(lauuul
	 vnctote '!,R	 / 11,1 S 3 4 0, • `:1 ^ O,nC,
x n • ti. '.,7+11,1:+ '',3r11,1lS X0,1
_1!111 ^ 115 11_'a+lryl ^ II,u4r
! !uu + Il+1 _4 1 1++ ^ 114 ^ 0,75
75,f 4R,2 iS,:f ^ li,(1 >O,UI
71.11+:1,, fii,3^G,4 X11,'!5
:{411	 4 i,1 "11 ,i + 1, fi ^(1,+'S
^,1i +0,1:4 ^ ^ +-0,1f ^U,14
Key:	 a. ^tystacpnic indices f. Slow ptk^se speed in microvolts/sec
b. Rotation clocktivise g. 'metal number of jerks
c. Rotation counterclockwise h. Length of reaction in seoc^nds
d. Prestest i. Average frequency in secorxis
e. Posttest
tionS there was a striking difference between these two groups of anin>als. In the
first seven rotation tests the nystagmic reaction of the hypokinetic anima ls and con-
trols dici not differ in any noticeable way. The difference appeared at test $:
	
/1007
the reaction of the controls decreased from one rotation to the next in a progress-
ive way, while in tha hypok.i*^etic animals it stayed at practically the same level.
Not one of the 8 tiypokinetic animals showed any noticeable reduction in reaction to
the selected nystagmic irxiices (Fig. 2, 3) .
LValuation. One might expect, that c:x^bility restriction might reduce the activity
of the vestibular receptors which normally react to a change in position of the head
or whole body in space as a result of their "non-use". The latter, as is well known,
leads to a w^aakening of afferentation and the bsildup of a stimulation deficit in
the centers that correspond to this affPZ'entation [16]. Activity of the vestibular
receptors may also be affected by chan<7es in the water-salt e.^cchanc?e and the hetrn-
dynamics noted, as a rule, in animals under conditions of moL^ility restriction [8, 9,
20]. Rosults of experiments have shown, that 30-clay hypo]cinesia had no effect on the
intensity of- the nystac^lrnLS itself: slaw phase speed, total jerks and length of re-
action in the animals were the same as before hynokine_Sia and practically the same
as for the controls (Table 1). This saygests, that in relatively prolonged hypokine-
sia there is no noticeable charx3e in the spastic processes on the ^y from the recep-
tors of the semicircular canals through the vestibular nuclei arx3 reticular ^orm3tion
4
of the brainstem to the oculorrotor. nuclei. This si^aation points t.o the maintenance
of control by the cerebellum, brainstem and cortex of the large hemispheres.
At the same time restriction of motor activity led to the disappearance of the
habituation of the vestibular system in respect to repeated angular acceleraticn. /1008
At this time it is hard to explain the reason far this phenomeru^n. The Trost signi-
ficant changes for rabbits ir. hypokinesia have been established in the erriocrine sy-
st^n [12J. By the end of a month's hypokinesia r^ arn^unt of oorticostero .ids and
catecholamines in the blood plasma, adrenal glaixis anti hypottalamus had dropped 2-4
times on the average and there was a sigrdficant increase in the electric stimulation
thresholds of the posterior hypothalamus indicating a reduction in its excitability
(7j .
Is not such a sharp reduction in the adrenal function the reason for the disap-
pearance of habituation in ^iypokinesia? This hypothesis is based on the general the-
sis concerning the lead role of the adrenergic system in adaptation -accanrodation re-
actions of the organism and especially in the function of .he reticular forration of
the brainstem, whose role in the pYtlerxinenon of habituation is well knc^^n r9j.
5
}.
RF^'F.RF'NC^^
1. Biryukov, Ye. N., L. I. Kakvsin et al., Kosnucheskaya biologiya 2, 74 (1967).
2. Bogachc^nko, V. P., Problemy kosmicheskoy biologii [ProhlemS of Spt^.ce Aiology] ,13,
hbsovw, 1969, p 171.
3. Buyanov, p. V., A. V. Bere^7avkin arxi N. V. Pi^•enko, Kosmicheskaya bioloyiya 1,
78 (1967).
4. Gorgiladze, G. I. and G. S. Kazanskaya, Fizol, zhurn. S.SSR 57, 45 (1971).
5. Dorokhova, E. I., (sc^: i.L4sn '' ? !^ve^ p. 109.
6. Yef imenko, G. D. , ibid, F^. 127_ .
7. ".arena, T. A., Predbolezn' [Pr^rnrbidity], Mosoaa, 1969, p. 245.
8. Krotov, V. P., Kosmicheskaya biologiya 2, 66 (1972).
1:	 9. Kul' kw, V. N. , (see item 7 above] , p. 249.
10. t^iikhasev, M. I., V. I. Sokolkov and M. A. Tikhonov [see item 2 above] p. 71.
11. Panov, A. G., V. S. hbzin, V. A. flelyankin, ibid, p. 133.
12. Parin, V. V. and B. M. Fedorav, Aviatsi^nnaya i kosmicheskaya maditsina [Avia-
tion and Space Medicine], 2, Nbscaw, 1969, p. 116.
13. Purakhin, Yu. N. and B. N. Petukhov, Fiziologicheskiye problemy detrenirovanno-
sti [Physiological Problems in Detraining], *bsoow, 1970, pp 17R, 188.
14. Seregin, M. S. et al. [see itefi 2 above] p. 78.
15. Sirmnenko, V. V., ibid, p. 42.
16. Sorokhtin, G. N., Reaktsii vozbudimykh sistem na defitsit vozbuzhdP.niya [Reac-
tion of Stimulated Systems to Lack of Stimulation], Moscow, 1968.
17. Khilov, K. L., A. Ye. Kurashvili and V. P. Rudenko [tee item 2 above), p. 182.
18. Chazov, Ye. I. and V. G. Ann^-uichenko, Aviats. i ;:^sm, med., Nbscxxa, 1965, p 471.
19. Yakovleva, I. Ya., V. P. Baranova an3 R. I. Matsnev, Vesti otorinolar. 6, 45
(1967) .
20. Yaremer:^, B. R., Pat^of.iziologiya ekstremal'nykh sostoyaniy [Pathophysiology
of F^ctreme Conditions], Leningrad, 1970, p. 116.
6


Influence of mobility restriction on habituation of the vestibular apparatus

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