Submitted on June 6, 2006
Accepted on March 20, 2008
MICTURITION SUPPRESSING REGION IN THE PERIAQUEDUCTAL GRAY OF THE MESENCEPHALON OF THE CAT
Atsushi Numata1*, Tatsuya Iwata2, Hiromichi Iuchi1, Narumi Taniguchi1, Masafumi Kita3, Naoki Wada3, Yuji Kato3, and Hidehiro Kakizaki1
1 Urology, Asahikawa Medical College, Asahikawa, Hokkaidou, Japan
2 Urology, Asahikawa Medcal College, Japan
3 Urology, Asahikawa Medical College, Japan
* To whom correspondence should be addressed. E-mail: anuma{at}asahikawa-med.ac.jp.
Purpose: The periaqueductal gray (PAG) of the mesencephalon has been implicated to be involved in the control of micturition. We investigated micturition suppressing region in the PAG of the cat.
Materials and Methods: Decerebrated 27 adult cats were used. A microelectrode was inserted stereotaxically into the PAG and a region was searched where electrical stimulation suppressed isovolumetric bladder contractions. Simultaneous stimulation of the pontine micturition center (PMC) and micturition suppressing region in the PAG was performed before and after an injection of bicuculline, GABAA blocker, into the PMC.
Results: Micturition suppressing region was found at the dorsolateral margin of the rostral PAG. Bladder contractions were not provoked by simultaneous stimulation of the PMC and micturition suppressing region in the PAG. However, after bicuculline injection into the PMC, partial bladder contractions were provoked by simultaneous stimulation of the PMC and micturition suppressing region in the PAG.
Conclusions: These results suggest that the dorsolateral margin of the rostral PAG includes micturition suppressing region that seems to have neural connections with the PMC. GABA is assumed to be one of neurotransmitters that are involved in the PMC inhibition from micturition suppressing region in the PAG.
