Hormonal modulation of neuronal cells behaviour in vitro

Area of Science:

• Neuroscience
• Developmental Biology
• Biochemistry

Background:

• Cholinergic neurotransmission is crucial for brain development and function.
• Enzymes like choline acetyltransferase (ChAT) and acetylcholinesterase (AChE) are key regulators of cholinergic signaling.
• The influence of growth factors and hormones on these enzymes during embryonic development is not fully understood.

Purpose of the Study:

• To investigate the effects of insulin and nerve growth factor (NGF) on ChAT and AChE activities in cultured embryonic rat mesencephalon.
• To determine how embryonic age influences the developmental trajectory of these cholinergic enzymes in vitro.
• To elucidate the specific roles of insulin and NGF in modulating cholinergic enzyme expression and activity.

Main Methods:

• Primary cell cultures were established from embryonic rat mesencephalon at different developmental stages (13-17 days in vitro).
• Enzyme activities of ChAT and AChE were measured over time in culture.
• Cultures were treated with varying concentrations of insulin and NGF to assess their impact on enzyme kinetics.

Main Results:

• ChAT activity generally increased with time in vitro, with variations dependent on embryonic age.
• AChE activity showed age-dependent changes: increasing in cultures from 13-day-old embryos and decreasing in those from 17-day-old embryos.
• Insulin inhibited ChAT activity but prevented AChE decrease in older embryos; NGF significantly increased ChAT activity (5-12 fold) without affecting AChE.

Conclusions:

• Both insulin and NGF play significant roles in modulating cholinergic enzyme activities during embryonic brain development.
• The effects of these factors are complex and depend on the specific enzyme, embryonic age, and exposure concentration.
• NGF is a potent stimulator of ChAT, suggesting a critical role in promoting cholinergic neuron maturation.