Related Experiment Videos
Neurotrophic action of VIP on spinal cord cultures
Abstract:
Vasoactive intestinal peptide-like immunofluorescence was observed in 3-5% of the neurons in 4 week old dissociated cultures from fetal mouse spinal cord and dorsal root ganglion. Radioimmunoassay indicated that VIP was spontaneously released into the culture medium. This release was inhibited by tetrodotoxin (TTX). Previous studies indicated that 50-60% of the spinal cord neurons die between days 7 and 21 in vitro. Blockade of electrical activity with TTX during days 8-15 resulted in a 30% decrease in the number of neurons as compared to control cultures. Addition of VIP (0.1 nM) to TTX-treated cultures prevented neuronal cell death. When VIP alone was added to the cultures, no significant difference in the number of neurons from controls was observed. The possibility that VIP influences cholinergic neurons was tested by measuring choline acetyltransferase (CAT) activity at various periods during development. A 48 hour treatment with 0.1 nM VIP increased CAT activity by 50%. The CAT stimulation was observed only during a period in development when naturally occurring neuronal cell death was taking place. The increases in CAT activity were dose dependent within a range of 10(-12) M to 10(-10) M VIP; however, higher concentrations of VIP attenuated the increases in enzyme activity.
Insights
Vasoactive intestinal peptide (VIP) prevents neuronal cell death in developing mouse spinal cord cultures by blocking electrical activity. VIP also enhances choline acetyltransferase activity, crucial for cholinergic neuron development.
Area of Science:
- Neuroscience
- Developmental Biology
- Cell Biology
Background:
- Vasoactive intestinal peptide (VIP) is present in fetal mouse spinal cord and dorsal root ganglion neurons.
- Neuronal cell death is a significant event in spinal cord development in vitro.
- Electrical activity influences neuronal survival during development.
Purpose of the Study:
- To investigate the role of VIP in neuronal survival during development.
- To determine if VIP influences cholinergic neuron development.
- To examine the effects of VIP on choline acetyltransferase (CAT) activity.
Main Methods:
- Dissociated cultures of fetal mouse spinal cord and dorsal root ganglion were used.
- Radioimmunoassay was employed to detect VIP release.
- Tetrodotoxin (TTX) was used to block electrical activity.
- Choline acetyltransferase (CAT) activity was measured to assess cholinergic neuron development.
Main Results:
- VIP was spontaneously released into the culture medium and its release was inhibited by TTX.
- Blocking electrical activity with TTX increased neuronal cell death by 30%.
- Addition of 0.1 nM VIP prevented TTX-induced neuronal cell death.
- VIP treatment (0.1 nM) increased CAT activity by 50% during the period of natural neuronal cell death.
- CAT stimulation by VIP was dose-dependent within a specific concentration range.
Conclusions:
- VIP plays a protective role against activity-dependent neuronal cell death in the developing spinal cord.
- VIP promotes the development of cholinergic neurons by increasing CAT activity.
- VIP's neurotrophic effects are concentration-dependent and occur during critical developmental periods.