Role of spinal metabotropic glutamate receptors in regulation of lower urinary tract function in the decerebrate unanesthetized rat

Neurosci Lett, 2007 · DOI: · Published: June 8, 2007

Simple Explanation

This study investigates how certain receptors in the spinal cord, called metabotropic glutamate receptors (mGluRs), affect bladder and urethral sphincter function in rats. The researchers used a drug (MCPG) to block these receptors and then measured bladder contractions and urethral sphincter muscle activity. They found that blocking these receptors in rats with intact spinal cords increased urethral sphincter activity, suggesting these receptors normally inhibit the sphincter. This effect was not seen in rats with spinal cord injuries.

Study Duration

3-4 weeks post-spinalization

Participants

13 Sprague-Dawley female rats

Evidence Level

Not specified

Key Findings

1
In spinal cord intact rats, blocking group I/II mGluRs with MCPG facilitated EUS EMG activity at a dose of 100 μg.
2
MCPG had no significant effect on bladder activity in spinal cord intact rats.
3
In chronically spinal cord transected rats, MCPG did not alter activity of either the EUS EMG or the bladder.

Research Summary

This study investigated the role of spinal metabotropic glutamate receptors (mGluRs) in the control of lower urinary tract functions in rats. The results suggest that group I/II mGluRs are likely involved in the inhibition of the excitatory pathway to the EUS but not the bladder. The lack of effect of MCPG on the EUS EMG activity in chronic SCT rats indicates that mGluR-mediated inhibitory control of the EUS was eliminated after spinal cord injury.

Practical Implications

Potential therapeutic target

Spinal mGluRs, particularly mGluR1, may be a useful target for drugs to alleviate lower urinary tract dysfunction, especially detrusor-sphincter dyssynergia.

Understanding Spinal Cord Injury Effects

The study suggests that spinal cord injury eliminates mGluR-mediated inhibitory control of the EUS, which may contribute to uncoordinated bladder and sphincter activity.

EUS Activity Modulation

The spinal metabotropic glutamatergic mechanism is involved in the inhibitory modulation of the glutamatergic excitatory input to the EUS via the AMPA and/or NMDA receptors in spinal cord intact rats.

Study Limitations

1
The pattern of EUS EMG activity was not analyzed
2
Study conducted on decerebrate unanesthetized rats, which may not fully represent normal physiological conditions.
3
Focus on group I/II mGluRs; other mGluR subtypes may also play a role.

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