Muscarinic M₁, M₃ receptor modulation in the corpus striatum of streptozotocin induced diabetic rats as a function of age.
OBJECTIVE
In this study we have investigated muscarinic M₁, M₃ receptor kinetics and the functional role of IP3 and cGMP in the corpus striatum of both young and old diabetic and insulin-treated diabetic rats.


METHODS
Radioreceptor binding assays was done in the corpus striatum using specific antagonists QNB and DAMP. IP3 and cGMP assay using [3H]IP3 and [3H]cGMP Biotrak assay system kits.


RESULTS
M₁ receptor increased and M₃ receptor decreased in control old rats when compared with young control rats. In young diabetic groups M₁ receptor increased and M₃ receptor decreased. Old diabetic groups showed reversed M₁ and M₃ receptors compared with their controls. IP3 and cGMP content increased in old control rats compared with young control rats. IP3 content increased in young diabetic rats and decreased in old diabetic rats. cGMP content was increased significantly in both young and old diabetic groups. Insulin treatment reversed these altered parameters near to control.


CONCLUSIONS
Our studies showed that M₁ and M₃ receptors, IP3 and cGMP were functionally regulated during diabetes as function of age, which will have immense clinical significance.
Molecular Neurobiology and Cell Biology Unit, Centre for Neuroscience, Department of Biotechnology, Cochin University of Science and Technology, Cochin, Kerala, India.
Balakrishnan
B
Savitha
Peeyush
P
Kumar
Mary A
MA
Pretty
George
G
Naijil
Chiramadathikudiyil S
CS
Paulose
D000367:Age Factors; D000818:Animals; D001786:Blood Glucose / Q000378:metabolism; D001835:Body Weight / Q000187:drug effects; D002352:Carrier Proteins / Q000378:metabolism; D003342:Corpus Striatum / Q000378:metabolism*; D003921:Diabetes Mellitus, Experimental / Q000188:drug therapy* / Q000378:metabolism*; D003924:Diabetes Mellitus, Type 2 / Q000188:drug therapy* / Q000378:metabolism; D015544:Inositol 1,4,5-Trisphosphate / Q000378:metabolism; D007328:Insulin / Q000008:administration & dosage / Q000627:therapeutic use*; D047908:Intracellular Signaling Peptides and Proteins / Q000378:metabolism; D008297:Male; D051381:Rats; D017208:Rats, Wistar; D043643:Receptor, Muscarinic M1 / Q000378:metabolism*; D043587:Receptor, Muscarinic M3 / Q000378:metabolism*; D013311:Streptozocin
D001786:Blood Glucose; D002352:Carrier Proteins; D007328:Insulin; D047908:Intracellular Signaling Peptides and Proteins; D043643:Receptor, Muscarinic M1; D043587:Receptor, Muscarinic M3; C022994:cyclic GMP-binding protein; D013311:Streptozocin; D015544:Inositol 1,4,5-Trisphosphate