Renuka, T R; Ani Das, V; Paulose, C S(Department of Biotechnology, March 2, 2004)
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Abstract:
Muscarinic M1 and M3 receptor changes in the brain stem during pancreatic regeneration were investigated.
Brain stem acetylcholine esterase activity decreased at the time of regeneration . Sympathetic activity also
decreased as indicated by the norepinephrine (NE) and epinephrine (EPI) content of adrenals and also in the
plasma. Muscarinic Ml and M3 receptors showed reciprocal changes in the brain stem during regeneration.
Muscairnic M1 receptor number decreased at time of regeneration without any change in the affinity. High affinity
M3 receptors showed an increase in the number. The affinity did not show any change . The number of low affinity
receptors decreased with decreased Kd at 72 hours after partial pancreatectomy. The Kd reversed to control value
with a reversal of the number of receptors to near control value . Gene expression studies also showed a similar
change in the mRNA level of Ml and M3 receptors . These alterations in the muscarinic receptors regulate
sympathetic activity and maintain glucose level during pancreatic regeneration. Central muscarinic M1 and M3
receptor subtypes functional balance is suggested to regulate sympathetic and parasympathetic activity, which in
turn control the islet cell proliferation and glucose homeostasis.
Mohanan,Valiyaveettil; Balarama Kaimal,S; Paulose,Cheramadathikudyil S(Department of Bio Technology, August 30, 2004)
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Abstract:
The present study was to investigate the rote of central 5-11T and 5-HT,:v receptor Lindin4o
and acne expression in it 'at mo(lel of pancreatic regeneration using 60" -, pancreatcutumy.
The pancreatic regeneration was evaluated by 5-HT content and 5-HT,,receptor gene
expression in the cerebral cortex (CC) and brain stem MS) of Alain opcrate,t, 7 It utd
7 (.lays panereatectomised rats. 5-11T content significantly increased in the CC' (I' 1.1)11
and 13S (P 0.05) of 72 Ii p.ntcreateetomiscd rats. Sympathetic activity was decreased as
indicated by the significantly decreased norcpiuephrine (NIi) and epinephrine (FTI) Icvcl
(1' < 0.001 and P < 0.05) in the plasma of 72 h panereateetomised rats. 5-111 ,^, receptor
density and affinity was decreased in the CC (P < 0.01) and BS (P < 0.01). These rh:)nge;
correlated with a diminished 5-IITIA receptor mRNA expression in the brain region. studied.
Our resuils suggest that the brain 5-11T through 5-HTin receptor has it funcuon:0 rule
iii 11w pi+ncreatic regcner:ttion through the sympathetic regulation.
Mohanan, Valiya Veettil; Finla, Chathu; Paulose, Cheramadathikudyil S(Department of Bio Technology, December 1, 2004)
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Abstract:
The purpose of this study was to investigate the role of central 5-HT2C receptor binding in rat model of pancreatic regeneration
using 60-70% pancreatectomy. The 5-HT and 5-HT2c receptor kinetics were studied in cerebral cortex and brain stem of sham
operated, 72 h pancreatectomised and 7 days pancreatectomised rats. Scatchard analysis with [3H] mesulergine in cerebral
cortex showed a significant decrease (p < 0.05) in maximal binding (B^,ax) without any change in Kd in 72 h pancreatectomised
rats compared with sham. The decreased Bmax reversed to sham level by 7 days after pancreatectomy. In brain stem , Scatchard
analysis showed a significant decrease (p < 0.01) in Bax with a significant increase (p < 0.01) in Kd. Competition analysis
in brain stem showed a shift in affinity towards a low affinity. These parameters were reversed to sham level by 7 days after
pancreatectomy. Thus the results suggest that 5-HT through the 5-HT2C receptor in the brain has a functional regulatory role in
the pancreatic regeneration. (Mol Cell Biochem 272: 165-170, 2005)