Abstract:
The abnormal resistance at peripheral nerve
to ischaeoia observe ! i n c e r t a i n disease conditions -
diabetes n e l l i tus, chronic l i v o r disease, notor
n«i»rone disease and allexan-diah ^>test has boon
— p l a t a s r t by Semevirfttne and P e i r i s on the '«als of
a defective periaxonal diffusion b a r r i e r * I t i a
thought that i n the healthy nerves during lechao^la,
the intact barrier serves to accumulate the E #
leasing free the axon against the axona1 surface thus
causing a depolarisation conduction block- In t h is
study the e f f e c t of increasing the K* cent nt within
the periaxonal space, on nerve e x c i t a b i l i t y have
been investigated* The e f f e c t of iachaowia oa the
peripheral nerve of these fiyporkalacaic cats ha*
also b «en studied to ascertain the role of K*
dynamics i n tha periaxonal space la the isehaeelc
1 m o t i v a t i o n process. In the second part of the
study an attempt Has been »ade to identify this
barrier s t r u c t u r a l l y and to doooostrate h i s t o l o g i c al
encages of t h i s barrrler i n the d i a b e t i c condition*
Has results of these exr»erinent* conple^ent the
res a l t a obtained free physiological etndloe on the
periaxonal d i f f u s i o n barrier of diabetic nerve•
From the r e s u l t * of t h i s study It has been
concluded that the para we >fsi gap substance at the
nodes of Ranvler constitute the postulated periaxonal
diffusion b a r r i e r * Further* a reduction In the
cation hlndlne capacity of t h i s cap rebalance i n
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the nerves of diabetic subjects and alloxan«>diabctle
rata has been demonstrated. Tha possible antecedent
biochemical changes which lead to the altered
staining propertiss of the gap substance are
examined. \ correlation between Schwann c e ll
ostabolisn in segmental deayelin&tlon and chAJigee
of the gap substance i s suggested
