A role for protein kinase C in astrocyte glycogen metabolism | JoVE Visualize

A role for protein kinase C in astrocyte glycogen metabolism

¹Biology Department, Open University, Milton Keynes, U.K.

Neuroscience Letters|July 19, 1988

View abstract on PubMed

Summary

Protein kinase C (PKC) activation reduces astrocyte glycogen labeling by 30%. Forskolin increases glycogen turnover, an effect amplified by combined PKC and adenylate cyclase activation, suggesting pathway interaction.

Area of Science:

Neuroscience
Cell Biology
Biochemistry

Background:

Astrocytes play crucial roles in brain energy metabolism.
Astrocyte glycogen metabolism is vital for neuronal function and energy supply.
Understanding astrocyte signaling pathways is key to comprehending brain energy homeostasis.

Purpose of the Study:

To investigate the role of protein kinase C (PKC) in regulating astrocyte glycogen metabolism.
To explore the interplay between PKC and adenylate cyclase signaling in astrocytes.
To elucidate the mechanisms controlling astrocyte glycogen turnover.

Main Methods:

Primary astrocyte cultures were utilized.
Cells were incubated with 2-[3H]deoxyglucose (2-DG) to measure glycogen incorporation.
Stimulation with phorbol 12-myristate 13-acetate (PMA), dioctanoylglycerol, and forskolin was performed.
Protein kinase C (PKC) depletion was achieved through prior PMA exposure.

Main Results:

Phorbol ester (PMA) and diacylglycerol analogue reduced 3H incorporation into astrocyte glycogen by 30%.
This reduction was abolished in PKC-depleted astrocytes, confirming PKC's inhibitory role.
Forskolin increased glycogen labeling by 40%, indicating enhanced turnover.
Combined forskolin and PMA treatment potentiated the forskolin-induced increase in glycogen labeling.

Conclusions:

Protein kinase C (PKC) activation inhibits astrocyte glycogen synthesis.
Adenylate cyclase activation enhances astrocyte glycogen turnover.
There is a significant interaction between PKC and adenylate cyclase signaling pathways in regulating astrocyte glycogen metabolism.
These findings highlight complex regulatory mechanisms governing brain energy metabolism by astrocytes.