Related Experiment Videos
Striatal cholinergic interneurons: birthdates predict compartmental localization
E H van Vulpen1, D van der Kooy
1Department of Anatomy and Cell Biology, University of Toronto, Ontario, Canada.
Insights
Area of Science:
- Neuroscience
- Developmental Neurobiology
- Striatal Circuitry
Background:
- Striatal neurons exhibit distinct compartmentalization into patch and matrix based on their birthdates.
- Cholinergic interneurons, born early in neurogenesis, are unexpectedly distributed throughout the striatum, with a preference for the matrix.
- Understanding the factors influencing cholinergic interneuron localization is crucial for deciphering striatal function.
Purpose of the Study:
- To investigate whether neuronal birthdate predicts the final compartmental localization of striatal cholinergic interneurons.
- To compare the birthdate-compartment relationship of cholinergic neurons with other striatal neuron populations.
Main Methods:
- Maternal injection of bromodeoxyuridine (BrdU) to label postmitotic neurons at specific embryonic days (E13, E15, E17).
- Retrograde tracer (True Blue) injection into the substantia nigra to label the patch compartment.
- Triple labeling for BrdU, choline acetyltransferase (cholinergic marker), and True Blue in adult rats (P40).
Main Results:
- Cholinergic neurons born at E13 showed a higher probability of localization in the patch compartment.
- Cholinergic neurons born at E17 were more likely to be found in the matrix compartment, including the intermediate zone.
- The birthdate-dependent localization pattern for cholinergic neurons mirrors that of other striatal neuron types.
Conclusions:
- Neuronal birthdate is a significant predictor of compartmental localization for striatal cholinergic interneurons.
- The distribution of cholinergic interneurons, including those in the intermediate zone, follows a birthdate-dependent gradient.
- While absolute birthdates are earlier, cholinergic neurons exhibit the same relative birthdate/compartment relationship as other striatal neurons.
Abstract:
The striatal patch and matrix compartment neurons are born at different times during rat development. The majority of the early born neurons preferentially end up in the patch compartment, while the majority of the later born neurons end up in the matrix compartment. Although the cholinergic interneurons are all born early in neurogenesis (between embryonic day E12 and E17), and we would therefore expect them to be located mainly in the patches, they are relatively homogeneously distributed in the adult, with a preference for the matrix area just outside the patches (the intermediate zone). To ask if birthdate can predict the compartmental localization of cholinergic neurons in the striatum, we marked new postmitotic neurons in the embryo with a maternal injection of bromodeoxyuridine (BrdU) on E13, E15 or E17 and labeled the patch compartment with an injection of the retrograde tracer True Blue into the substantia nigra on postnatal day (P) 1. The pups were sacrificed at P40 and the tissue was processed for BrdU, choline acetyltransferase, and True Blue triple labeling. Cholinergic neurons that became postmitotic at E13, had a higher chance of ending up in the patch compartment compared to either the intermediate zone or the rest of the matrix compartment. On the other hand cholinergic neurons that became postmitotic at E17 had a higher chance of ending up in the matrix compartment (including the intermediate zone). We conclude that birthdate can predict compartmental localization, with the cholinergic neurons in the intermediate zone following the same pattern as the cholinergic neurons in the rest of the matrix compartment. Cholinergic neurons show the same relative birthdate/compartment relationship as do other striatal neurons, although the absolute birthdates of cholinergic neurons are shifted earlier in neurogenesis.