Octopamine is involved in TRP-induced thermopreference responses in American cockroach

Area of Science:

• Neuroscience
• Insect Physiology
• Sensory Biology

Background:

• Insect thermoregulation relies on thermosensation and neural processing.
• Transient Receptor Potential (TRP) channels are known thermoreceptors.
• The role of neurotransmitters in insect thermoregulation is largely unknown.

Purpose of the Study:

• To investigate the involvement of octopamine in TRP channel-induced thermoregulatory responses in the American cockroach, Periplaneta americana.
• To determine if octopamine acts as a neurotransmitter in insect heat sensation pathways.

Main Methods:

• Used capsaicin to activate heat-sensitive TRP channels (Painless) in cockroaches.
• Assessed behavioral (thermal preference, grooming), physiological (heart rate), and biochemical responses.
• Administered capsaicin, octopamine, and phentolamine (an octopaminergic receptor blocker).

Main Results:

• Capsaicin induced thermoregulatory behavior, increased grooming, and elevated heart rate, similar to octopamine.
• Octopamine levels and protein kinase A (PKA) activity increased post-capsaicin treatment.
• Phentolamine blocked capsaicin-induced responses, including behavior, grooming, and heart rate.

Conclusions:

• Octopamine is a neurotransmitter released upon activation of insect heat receptors.
• Octopamine mediates TRP channel-induced thermoregulatory behaviors and physiological changes in cockroaches.
• This study elucidates a novel neurotransmitter pathway in insect thermosensation.