Forebrain muscarinic control of micturition reflex in rats.
Functional contribution of the cholinergic pathway between the frontal cortex and basal nucleus of Meynert to micturition reflex was investigated. Male Wistar rats were subjected to bilateral lesion of the basal forebrain by ibotenic acid (IA) injection (7.5 microg/rat on each side) (BF rats). Phosphate buffered saline (PBS) was injected into control rats (sham operated rats; SO rats). Cystometrograms were obtained from conscious BF and SO rats 7-10 days after IA/PBS injection. Bladder capacity (BC) of BF rats was significantly smaller than that of SO rats (approximately 43.7%) and was accompanied by decrease in choline-acetyltransferase activity in the frontal cortices. Oxotremorine M, a muscarinic receptor agonist, increased BC in BF rats, while pirenzepine, an M1 muscarinic receptor antagonist, counteracted the effect of the oxotremorine M-induced increase in BC. Injection of oxotremorine M into the dorsal pontine tegmentum (DPT) reduced BC in BF and SO rats, while injection of pirenzepine had no effect on cystometrograms. These findings indicate that the M1 muscarinic receptor plays a part in the forebrain inhibitory mechanisms involved in the micturition reflex and that muscarinic receptor in the DPT contributes to excitatory control of micturition reflex.
Yokoyama
O
O
Department of Urology, Kanazawa University School of Medicine, 920-8641, Ishikawa, Kanazawa, Japan. oyoko@med.kanazawa-u.ac.jp
Ootsuka
N
N
Komatsu
K
K
Kodama
K
K
Yotsuyanagi
S
S
Niikura
S
S
Nagasaka
Y
Y
Nakada
Y
Y
Kanie
S
S
Namiki
M
M
D000818:Animals; D020532:Basal Nucleus of Meynert / Q000187:drug effects / Q000502:physiology; D004305:Dose-Response Relationship, Drug; D018690:Excitatory Amino Acid Agonists; D007051:Ibotenic Acid; D008297:Male; D018721:Muscarinic Agonists / Q000494:pharmacology; D010095:Oxotremorine / Q000494:pharmacology; D016548:Prosencephalon / Q000187:drug effects / Q000502:physiology*; D051381:Rats; D017208:Rats, Wistar; D043643:Receptor, Muscarinic M1; D011976:Receptors, Muscarinic / Q000502:physiology*; D012018:Reflex / Q000187:drug effects* / Q000502:physiology; D001743:Urinary Bladder / Q000187:drug effects / Q000502:physiology*; D014554:Urination / Q000187:drug effects* / Q000502:physiology
D018690:Excitatory Amino Acid Agonists; D018721:Muscarinic Agonists; D043643:Receptor, Muscarinic M1; D011976:Receptors, Muscarinic; D007051:Ibotenic Acid; D010095:Oxotremorine