Ventrolateral Periaqueductal Gray Neurons Are Active During Urination

Area of Science:

• Neuroscience
• Urology

Background:

• The ventrolateral periaqueductal gray (VLPAG) is implicated in bladder control.
• Neural pathways from the VLPAG to the pontine micturition center (PMC) are key to initiating urination.
• Gaps exist in understanding VLPAG neuron location, activity, and inputs related to bladder control.

Purpose of the Study:

• To identify the distribution and function of VLPAG neurons involved in bladder control.
• To elucidate the whole-brain inputs to PMC-projecting VLPAG neurons.
• To clarify the role of VLPAG in the neural circuitry of micturition.

Main Methods:

• Retrograde neural tracing to map VLPAG neuron distribution and PMC projections.
• In vivo population Ca2⁺ imaging in freely moving animals to record neuronal activity during urination.
• RV-based retrograde trans-synaptic tracing to identify upstream neural inputs.

Main Results:

• Identified VLPAG neurons projecting to the PMC, potentially involved in bladder control.
• Population Ca2⁺ signals of PMC-projecting VLPAG neurons strongly correlated with bladder contractions and urination.
• Revealed dense inputs to these VLPAG neurons from brain regions including the medial preoptic area, medial prefrontal cortex, and lateral hypothalamus.

Conclusions:

• The VLPAG plays a significant role in bladder function through its projections to the PMC.
• Urination-related PMC-projecting VLPAG neurons receive input from higher brain centers.
• These findings offer insights into bladder control mechanisms and potential therapeutic strategies for neurogenic bladder dysfunction.