title: Participation of caudal ventrolateral medulla in the regulation of gallbladder motility in rabbits.
abstract: 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.
authors.affiliation: Department of Physiology, School of Medicine, Shanldong University, Jinan 250012, Shandong Province, PR China.
authors.forename: Feng-Yu
authors.initials: FY
authors.lastname: Liu
authors.forename: Chuan-Yong
authors.initials: CY
authors.lastname: Liu
authors.forename: Jing-Zhang
authors.initials: JZ
authors.lastname: Liu
authors.forename: Dong-Ping
authors.initials: DP
authors.lastname: Xie
mesh_terms: 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*
chemical_list: 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