Neuropeptide Modulation Increases Dendritic Electrical Spread to Restore Neuronal Activity Disrupted by Temperature

Area of Science:

• Neuroscience
• Cellular Physiology
• Biophysics

Background:

• Acute temperature changes can disrupt neuronal activity, leading to motor control loss and impaired vital behaviors.
• The cellular mechanisms by which neuropeptides maintain temperature-robust neuronal function are largely unknown.
• Central pattern generators (CPGs) are crucial for rhythmic motor activities, but their function is temperature-sensitive.

Purpose of the Study:

• To investigate how peptide neuromodulation preserves neuronal activity against acute temperature increases.
• To elucidate the cellular actions of neuropeptides in maintaining temperature-robust CPG function.
• To identify neurophysiological mechanisms underlying neuropeptide-mediated temperature compensation.

Main Methods:

• Utilized the crustacean gastric mill CPG model to study temperature effects on neuronal activity.
• Applied electrophysiology and fluorescent calcium imaging to assess neuronal responses.
• Investigated the role of Cancer borealis tachykinin-related peptide Ia (CabTRP Ia) in restoring neuronal function.
• Employed dynamic clamp to isolate the effects of specific ionic conductances.

Main Results:

• Warming compromised spike generation and rhythmic activity in CPG neurons by decreasing membrane resistance and shunting dendritic signals.
• CabTRP Ia application restored rhythmic activity by reducing membrane shunt and enhancing dendritic electrical spread.
• Neuropeptide modulation improved the propagation of postsynaptic potentials and action potentials within the neuron.
• The voltage-dependent conductance activated by CabTRP Ia was sufficient to restore rhythmic bursting in temperature-compromised neurons.

Conclusions:

• Peptide neuromodulation, specifically by CabTRP Ia, counteracts detrimental temperature effects on neuronal activity.
• Neuropeptides enhance dendritic electrical spread, crucial for maintaining neuronal function under thermal stress.
• This study reveals a key mechanism for neuropeptide action in supporting temperature-robust neural pattern generation.