Central GABAergic neuromodulation of nocifensive behaviors in bumble bees.

In mammals, nocifensive behaviors are modulated by neuroactive compounds indicating a complex pain-processing system. This study aimed to assess the role of gamma-aminobutyric acid (GABA) in modulating nocifensive behaviors in the bumble bee to better understand how pain-like behaviors are regulated in insects. Results showed that oral administration of gabapentin (0.24 mg/mL), a GABAergic analgesic acting at the central level, reduced heat sensitivity, making bees more likely to pass through a tunnel heated to 50°C, and suppressed their nocifensive behaviors. Gene expression analysis revealed a significant increase in brain expression of GAD1 in response to noxious stimulation. These findings indicate that GABA plays a key role in modulating nocifensive behaviors in insects, similar to its role in mammals, suggesting that insects may possess mechanisms for pain modulation that go beyond simple peripheral responses.