Participation of caudal ventrolateral medulla in the regulation of gallbladder motility in rabbits.
To investigate whether the caudal ventrolateral medulla (CVLM) participates in the regulation of gallbladder motility, we studied the effects of microinjection of L-glutamate and other agents into the CVLM on gallbladder pressure (GP) in anesthetized rabbits. A frog bladder connected with a force transducer was inserted into the gallbladder to record the change of GP. Microinjection of L-glutamate into the CVLM decreased GP, While micnoinjection of gamma-amino-butyric acid (GABA) increased GP. Microinjection of ketamine, a noncompetitive N-methyl-D-aspartate (NMDA) receptor antagonist, into CVLM increased GP, while microinjection of 6-cyano-7-nitroquinoxaline-2,3-(1H,4H)-dione (CNQX), a competitive (+/-)-a-amino-3-hydroxy-5-methylisoxazole-4-propionic acid (AMPA)/kainate receptor antagonist, had no significant effect on GP. The effects of L-glutamate was abolished by ketamine, but not by CNQX. Intravenous injection of phentolamine or transection of the spinal cord eliminated the effects of L-glutamate on GP. These results indicate that [1] CVLM participated in the regulation of gallbladder motility; [2] endogenous L-glutamate in CVLM is involved in the regulation mediated by NMDA receptors, the output of which is sent through sympathetic nerve and alpha-adrenergic receptors.
Liu
Feng-Yu
FY
Department of Physiology, School of Medicine, Shanldong University, Jinan 250012, Shandong Province, PR China.
Liu
Chuan-Yong
CY
Liu
Jing-Zhang
JZ
Xie
Dong-Ping
DP
D018750:6-Cyano-7-nitroquinoxaline-2,3-dione / Q000494:pharmacology; D000818:Animals; D001001:Anura; D018691:Excitatory Amino Acid Antagonists / Q000494:pharmacology; D005260:Female; D005704:Gallbladder / Q000294:innervation / Q000502:physiology; D016473:Gallbladder Emptying / Q000187:drug effects / Q000502:physiology*; D018698:Glutamic Acid / Q000008:administration & dosage*; D007649:Ketamine / Q000494:pharmacology; D008297:Male; D008526:Medulla Oblongata / Q000187:drug effects / Q000378:metabolism*; D008845:Microinjections; D009434:Neural Pathways / Q000502:physiology; D011312:Pressure; D011817:Rabbits; D018091:Receptors, AMPA / Q000037:antagonists & inhibitors; D016194:Receptors, N-Methyl-D-Aspartate / Q000037:antagonists & inhibitors / Q000378:metabolism / Q000502:physiology*; D013564:Sympathetic Nervous System / Q000502:physiology; D005680:gamma-Aminobutyric Acid / Q000008:administration & dosage*
D018691:Excitatory Amino Acid Antagonists; D018091:Receptors, AMPA; D016194:Receptors, N-Methyl-D-Aspartate; D018698:Glutamic Acid; D005680:gamma-Aminobutyric Acid; D007649:Ketamine; D018750:6-Cyano-7-nitroquinoxaline-2,3-dione