Elevated temperature alters the ionic dependence of amine-induced pacemaker activity in a conditional burster neuron

Area of Science:

• Neuroscience
• Computational Neuroscience
• Cellular Neuroscience

Background:

• The anterior burster neuron in lobsters acts as a key pacemaker for motor networks.
• This neuron's bursting activity is modulated by inputs and can be restored by monoamines like dopamine, octopamine, and serotonin.
• Previous research indicated temperature-dependent ionic dependencies for amine-induced bursting.

Purpose of the Study:

• To investigate how ambient temperature influences the ionic mechanisms underlying amine-induced rhythmic bursting in the anterior burster neuron.
• To determine if temperature affects the specific ion channel requirements (sodium and calcium) for dopamine, octopamine, and serotonin to induce oscillations.

Main Methods:

• Experiments were conducted on the anterior burster neuron of the lobster stomatogastric ganglion.
• Ionic dependencies were tested at two temperatures (15°C and 21°C) using solutions with altered sodium or calcium concentrations, and tetrodotoxin to block sodium currents.

Main Results:

• At 21°C, all tested amines (dopamine, octopamine, serotonin) could induce oscillations even when sodium currents were blocked by tetrodotoxin.
• Dopamine-induced oscillations at 21°C required both calcium and sodium currents.
• Serotonin-induced oscillations showed no dependence on calcium or sodium alone, while octopamine-induced oscillations were independent of calcium and variably dependent on sodium.

Conclusions:

• The ionic mechanisms supporting rhythmic bursting in the anterior burster neuron are flexible and depend on both the specific neuromodulator and the ambient temperature.
• This temperature- and modulator-dependent plasticity allows for diverse ionic pathways to generate coordinated motor network activity.