Anatomical brain structure of Perognathus longimembri

Lindberg, R. G.

English

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N S L  64-29-11 
PROGRESS REPORT 
INVESTIGATION OF PEROGNATHUS AS AN EXPERIMENTAL ORGANISM 
FOR RESEARCH IN SPACE BIOLOGY 
E -  
! 
1 A p r i l  through 30 June 1966 
R. G .  L i n d b e r g ,  Ph .D.  
P r i n c i p a l  Inves t iga to r  
PREPARED UNDER CONTRACT NASW-8 1 2  
€or  
O F F I C E  OF SPACE S C I E N C E S  
NATIONAL AERONAUTICS AND SPACE ADMINISTRATION 
WASHINGTON, D. C .  20546 
NORTHROP SPACE LABORATORIES 
3401 WEST BROADWAY 
HAWTHORNE, CALIFORNIA 903 5n 
https://ntrs.nasa.gov/search.jsp?R=19660024782 2020-03-16T20:19:34+00:00Z
I n v e s t i g a t i o n  of Perognathus a s  an 
Experimental Organism f o r  Research i n  
Space Biology (Contract  NASw-812) 
1 Apr i l  through 30 June 1966 
R. G .  Lindberg, Ph.D. 
P r i n c i p a l  I n v e s t i g a t o r  
D i r e c t o r ,  L i f e  Sciences 
Northrop Space Labora to r i e s  
3401 West Broadway 
Hawthorne, C a l i f o r n i a  90250 
NSL 64-29-11 .. 
. 
ANATOMY OF THE BRAIN OF PEROGNATHLJS LONGIMEMBRIS 
Ky l l ikk i  Grubel 
I. INTRODUCTION 
When an  animal e n t e r s  h ibe rna t ion ,  c e r t a i n  changes t a k e  p l a c e  i n  i t s  
The body temperature  dec reases  from normothermic l e v e l s ,  body func t ions .  - 37OC, down t o  0 - 2 O C  above t h e  ambient temperature.  
and b a s a l  me tabo l i c  r a t e  d e c l i n e .  Heat product ion d i sappea r s .  Heart  r a t e  
and r e s p i r a t o r y  r a t e  decrease.  
observed t o  t a k e  p l a c e  v a r i e s  somewhat from s p e c i e s  t o  species, bu t  body 
temperatures  appear  t o  be subse rv ien t  t o  t h e  changes i n  r e s p i r a t i o n ,  h e a r t  
r a t e  o r  oxygen consumption (Hoffman, 1964). These phenomena a r e ,  however, 
on ly  a r e s u l t ,  n o t  t h e  cause,  of e n t r y  i n t o  h i b e r n a t i o n .  
h i b e r n a t i o n  i s  n o t  a s imple  passive abandonment of temperature  r e g u l a t i o n ,  
b u t  r a t h e r  thermoregulatory mechanisms become r e a d j u s t e d  a t  t h i s  t ime. 
It has been suggested t h a t  t h e s e  changes can be mediated on ly  v i a  t h e  
autonomic nervous system. Cer t a in  biochemical adjustments  o r  a process  
of a c c l i m a t i z a t i o n  t a k e s  p l a c e  i n  t h e  c e n t r a l  nervous system of t h e  prepared 
h i b e r n a t o r .  
Oxygen consumption 
The o r d e r  i n  which t h e s e  t h i n g s  can be 
Entry i n t o  
A s  h i b e r n a t i o n  ensues,  c e r t a i n  s p e c i f i c  s t r u c t u r e s  o r  pathways a r e  
s t i m u l a t e d  t o  r e g u l a t e  and coord ina te  t h e  p h y s i o l o g i c a l  changes a s  tempera- 
t u r e s  drop. Throughout h ibe rna t ion ,  t h e  p e r i p h e r a l  nervous system appears 
t o  have an  i n c r e a s e d  s e n s i t i v i t y  t o  c e r t a i n  s t i m u l i .  
c e r t a i n  s u b c o r t i c a l  a r e a s  remain f u n c t i o n a l ,  ensuring r e g u l a t i o n  of 
t empera tu re  and o f  c a r d i a c  and r e s p i r a t o r y  f u n c t i o n ,  w h i l e  t h e  h ighe r  
c e n t e r s  become reduced i n  a c t i v i t y  b u t  may ma in ta in  a c e r t a i n  minimal 
f u n c t i o n  (Hoffman, 1964). T h e  temperature r e g u l a t i o n  i s  governed p r i m a r i l y  
by t h e  thermodetectors  of t h e  hypothalamus, and it  i s  p o s s i b l e  t h a t  some 
biochemical changes t a k e  p l a c e  i n  t h i s  a r e a  of  t h e  b r a i n  p r i o r  t o  t h e  e n t r y  
i n t o  h i b e r n a t i o n .  These s p e c u l a t i v e  biochemical changes i n  t h e  hypothalamus 
may be t h e  t r i g g e r i n g  f a c t o r  f o r  e n t r y  i n t o  h i b e r n a t i o n .  
During t h i s  p e r i o d ,  
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Much more f a c t u a l  in format ion  i s  a v a i l a b l e  on t h e  a r o u s a l  phase of 
A s  a r o u s a l  commences, t h e  t h o r a c i c  h i b e r n a t i o n  than  on t h e  e n t r y  phase. 
and brown f a t  temperature ,  h e a r t  r a t e ,  r e s p i r a t o r y  r a t e  and ca rd iac  ou tpu t  
i n c r e a s e  r ap id ly .  P e r i p h e r a l  vasocons t r i c t ion  res t r ic ts  t h e  increased  
blood flow most ly  t o  t h e  h e a r t  muscle, brown f a t ,  and r e s p i r a t o r y  muscles 
and p o s s i b l y  t h e  b r a i n  (Bul la rd  and Funkhouser, 1962). The thermogenic 
brown f a t  t i s s u e  rewarms t h e  b lood  c i r c u l a t i n g  through i t  (Smith and Rober t s ,  
1964), and thus  a i d s  i n  t h e  r ap id  rewarming of h e a r t ,  b r a i n  and r e s p i r a t o r y  
muscles .  The impor tan t  r o l e  of brown f a t  i n  a r o u s a l  of h ibe rna to r s  was 
shown by Smith and Hock i n  marmots (1963) and Smalley and Dryer i n  b a t s  
(1963). It appears ,  though, t h a t  t h e  a c t i v a t i o n  of brown f a t  t i s s u e  i s  
under  nervous c o n t r o l  (Kauppinen, Bul la rd  and Smith, 1964),  and t h a t  t h e  
thermoregulatory centers of hypothalamus t r i g g e r  t h e  spontaneous a r o u s a l s .  
I t  i s  most l i k e l y  t h a t  some biochemical changes t a k e  p l a c e  i n  t h e  hypo- 
thalamus dur ing  h i b e r n a t i o n  and t h a t  t h e s e  changes would cause  t h e  i n i t i a t i o n  
of a r o u s a l .  
This  r e p o r t  d e s c r i b e s  t h e  anatomy of t h e  b r a i n  of E .  longimembris. 
The t a s k  was undertaken t o  provide o r i e n t a t i o n  i n  t h e  i n t e r n a l  s t r u c t u r e s  
of  t h e  b r a i n  and t o  e s t a b l i s h  t h e  f e a s i b i l i t y  of  s tudying  t h e  neuro logica l  
b a s i s  of e n t r y  i n t o  and a r o u s a l  from h i b e r n a t i o n  us ing  E. longimembris 
a s  an experimental  animal.  
11. MATERIALS AND METHODS 
Four a d u l t  m i c e  of s p e c i e s  Perognathus longimembris w e r e  l i g h t l y  
a n e s t h e t i z e d  wi th  e t h e r  and then k i l l e d  by d e c a p i t a t i o n .  The b r a i n s  of t h e  
an imals  were e x t i r p a t e d ,  c u t  crosswise i n  two p a r t s  and p laced  i n  t o l u i d i n e  
b l u e  f i x a t i v e  and s t a i n  (Davenport, 1960).  A f t e r  about  one week's f i x a t i o n  
p e r i o d ,  t h e  b r a i n s  were f rozen  and sec t ioned  i n  50 u t h i c k  s l i c e s .  From 
t h e  f o u r  sec t ioned  b r a i n s ,  t h e  bes t  s l i d e s  were chosen t o  compose one 
r e p r e s e n t a t i v e  b r a i n  of E. longimembris. From t h i s  r e p r e s e n t a t i v e  b r a i n ,  
photographs were taken  from s e c t i o n s  a t  1 mm i n t e r v a l s .  
each  s e c t i o n  i n  ques t ion  i s  marked a s  a v e r t i c a l  l i n e  i n  t h e  drawing of a 
media l  s a g i t t a l  s e c t i o n  of a b ra in  ( f i g .  1). The s c a l e  o f  Figure 1 i s  15:1, 
and t h e  s c a l e  of t h e  c r o s s  s e c t i o n  photographs and l i n e  drawings ( f i g s .  2 - 8 )  
The l o c a t i o n  of 
is 2 8 : l .  
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The s m a l l  s i z e  of t h e  pocket  mouse precluded t h e  u s e  of s t anda rd  
s t e r e o t a x i c  appa ra tus  t o  e s t a b l i s h  coord ina te s .  The anatomical  s t r u c t u r e s  
of t h e  b r a i n  were i d e n t i f i e d ,  and t h e  nomenclature used i s  t h a t  found i n  
Kdnig and Kl ippe l  (1963). 
111. RESULTS 
The r e su l t s  a r e  p re sen ted  i n  t h e  fol lowing seven photographs and 
corresponding line drewings zf t h e  cross sec t ions  of  the b r a i n  of  
- P. longimembris ( f i g s  . 2-8). 
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LEGENDS TO THE FIGURES 
F i g u r e  1. Drawing of  a medial  s a g i t t a l  s e c t i o n  of t h e  b r a i n  of  E .  l ong i -  
membris. S c a l e  15:l. V e r t i c a l  l i n e s  1 - 7 mark t h e  corresponding c r o s s  
s e c t i o n  1 - 7, ( f i g s .  2 - 8). 
F i g u r e s  2a - 8a. Photographs of c r o s s  s e c t i o n s  of t h e  b r a i n  of E .  long<- 
membris. S c a l e  28:l .  
F igu res  2b - 8b. Line drawings of c r o s s  s e c t i o n s  of t h e  b r a i n  of 
- P .  longimembris. S c a l e  28:l .  
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IV. SUMMARY AND CONCLUSION 
The anatomy of t h e  b r a i n  of E. longimembris does n o t  d i f f e r  markedly 
from t h a t  of t h e  a l b i n o  ra t .  However, t h e  small s i z e  of t h e  animal and 
i t s  b r a i n  d i c t a t e s  t h e  need f o r  development of s p e c i a l  handl ing techniques 
and equipment i f  t h e  spec ie s  i s  t o  be used f o r  neurophys io logica l  research .  
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REFERENCES 
I. Bullard, R. W. and G. E. Funkhouser: Estimated regional blood flow by 
rubidium 86 distribution during arousal from hibernation. 
Am. J. Physiol. 203:266-270,  1962.  
2.  i j avenpr t ,  Ui A = :  Histological and histochemical technics, W. B. 
Saunders Co., Philadelphia, 1960,  401 pp. 
3 .  Hoffman, R. A . :  Terrestrial animals in cold: Hibernators. &I Hand- 
book of physiology, Sec. 4,  Adaptation to the environment, 
Am. Physiol. SOC., Waverly Press Inc., Baltimore, 1964.  
4 .  Kauppinen, K., R. W. Bullard and R. E. Smith: Tissue temperatures 
during arousal of hibernating ground squirrels. 
7 ( 3 ) ,  abstr., 1964.  
Physiologist 
5. Kdnig, J. F. R. and R. A .  Klippel: The rat brain, a stereotaxic 
atlas ..., Williams and Wilkins Co., Baltimore, 1963,  162 pp. 
6 .  Smalley, R. L. and R. L. Dryer: Brown fat: Thermogenic effect during 
arousal from hibernation in the bat. Science 140:1333-34,  1963.  
7 .  Smith, R. E. and R. J. Hock: Brown Fat: Thermogenic effector of 
arousal in hibernators. Science 140:199-20,  1963. 
8 .  Smith, R. E., and J. C. Roberts: Thermogenesis of brown adipose 
tissue in cold-acclimated rats. Am. J. Physiol. 206:143-148,  1964.  
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Investigation of Perognathus as an experimental organism for research in space biology Progress report, 1 Apr. - 30 Jun. 1966

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