Pius S,Padayatti; Paulose,C S(Department of Biotechnolgy, April 2, 1999)
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Abstract:
The brain stems (13S) of streptozotocin (STZ)-diabetic rats were studied lo see the changes in
neurotransmitter content and their receptor regulation. The norepinephrine (NE) content
determined in the diabetic brain stems did ^ control. an E showed la
while
PI turnover
hri
content increased significantly compared N^r eNveFa o the recep
significant increase. The alpha2 adrenergic receptor
IneP utisoulinntreat d ratsetheNE contentt dec^ sled
was significantly reduced during diabetes. in
versedcto reanorm
sed
ulcrea e tK
reatment
the
state.
while EPI content remained increased as in die diabetic
B,, for a]pha2 adrenergic receptors slw^nificantly while
Unlabelled clonidine inhibited [31-I]NE binding in BS of control, diabetic and insulin treated
ulations bindi
diabetic rats showed that alpha2 adrenergicre^ punks cojnidiabetic animal the ligand bound
sites with Hill slopes significantly away from unity.
weaker to the low affinity site than in controls. Insulin treatment reversed[ this allumbmn to
control levels. The displacement analysis using (-)-epinephrine age in
control and diabetic animals revealed two populations of receptor affinidtyo=tat ss. In control
animals, when GTP analogue added with epinephrine, the curve nagnlde caofnfitnroit yS
model; but in the diabetic BS this effect `not
aobserved. In
bintact
oth the diabetic
data thus showlthat
the effects of monovalent cations on affinity
alphaz adrenergic receptors have a reduced affinity v
due
in stem ialtered Itscppeomson(5-
regulation. The serotonin (5-HT) coat
hydroxy) tryptophan (5-HTP) showed an increase and its breakdown metabolite (5-hydroxy)
indoleacetic acid (5-I{IAA) showed a significant decrease. This showed that in serotonergic
which l
nerves there is a disturbance in both synthetic and breankduomwnbers pretma'med ana
increased 5-HT. The high affinity serotonin receptor um ese serotonerg
decrease in the receptor affinity. The insulin ^treatmentsturtiy showsha decreased serotonergic
receptor kinetic parameters to control level.
receptor function. These changes in adrenergic and serotonergic receptor function were
suggested to be important in insulin function during STZ diabetes.