Source Paper
BDNF Promotes the Regenerative Sprouting, But Not Survival, of Injured Serotonergic Axons in the Adult Rat Brain
Laura A. Mamounas, C. Anthony Altar, Mary E. Blue, David R. Kaplan, Lino Tessarollo et al.
Journal of Neuroscience • 2000
PCA-induced Serotonergic Axon Lesioning
Objective: To determine whether BDNF promotes survival of serotonergic axons during PCA-induced degeneration or facilitates regenerative sprouting after injury in the adult rat brain
Gather these items before starting the experiment. Check off items as you prepare.
As an Amazon Associate, we earn from qualifying purchases. Product links help support this free resource.
Protocol Steps
PCA Administration
Administer p-chloroamphetamine (PCA) neurotoxin to adult rats to induce serotonergic axon degeneration in the brain
Note: This creates the lesion model for studying serotonergic axon injury
View evidence from paper
“the severe loss of cortical 5-HT axons caused by the neurotoxin p-chloroamphetamine (PCA)”
Chronic BDNF Infusion
Deliver chronic intracortical BDNF infusions to test effects on serotonergic axon sprouting and regeneration
Note: BDNF treatment can be initiated up to one month after PCA administration
View evidence from paper
“BDNF treatment promoted the regrowth of 5-HT axons when initiated up to a month after PCA administration”
Dose-Response Study
Test multiple doses of BDNF to establish dose-response profiles for stimulating 5-HT sprouting and TrkB receptor signaling
Note: Both responses showed inverted-U-shaped dose-response curves with maximal effects at intermediate doses
View evidence from paper
“both responses were maximal at intermediate doses of BDNF but declined at higher doses”
Axon Sprouting Assessment
Evaluate sprouting of both intact and PCA-lesioned serotonergic axons at the neocortical infusion site
Note: BDNF markedly stimulates sprouting leading to hyperinnervation at the infusion site
View evidence from paper
“chronic BDNF infusions markedly stimulate the sprouting of both intact and PCA-lesioned 5-HT axons, leading to a hyperinnervation at the neocortical infusion site”
Long-term Persistence Assessment
Monitor persistence of sprouted serotonergic axons in cortex after terminating exogenous BDNF delivery
Note: Sprouted axons persist in cortex for extended period after BDNF treatment ends
View evidence from paper
“The sprouted axons persisted in cortex for at least 5 weeks after terminating exogenous BDNF delivery”
Hippocampal Sprouting Assessment
Evaluate regrowth of the serotonergic plexus in the hippocampus following BDNF treatment
Note: BDNF encourages regrowth only in lamina where 5-HT axons normally ramify
View evidence from paper
“BDNF also encouraged the regrowth of the 5-HT plexus in the hippocampus, but only in those lamina where 5-HT axons normally ramify”
TrkB Receptor Activation Analysis
Assess sustained local activation of the TrkB receptor following intracortical BDNF infusions
Note: Dose-response profiles for TrkB signaling activation are similar to those for 5-HT sprouting
View evidence from paper
“intracortical BDNF infusions induced a sustained local activation of the TrkB receptor”
TrkB Protein Analysis
Measure full-length TrkB protein, truncated TrkB protein, and TrkB mRNA levels to understand downregulation of Trk signal at excessive BDNF doses
Note: Decline in full-length TrkB protein occurs with excessive BDNF, but not truncated TrkB protein or mRNA
View evidence from paper
“Underlying the downregulation of the Trk signal with excessive BDNF was a decline in full-length TrkB protein, but not truncated TrkB protein or TrkB mRNA levels”