Caudal ventrolateral medulla mediates the depressor response elicited by the greater splanchnic nerve afferent stimulation in rats.
Caudal ventrolateral medulla (CVLM) plays an important role in the regulation of reflex cardiovascular activity. In the present study, the possible involvement of the CVLM in mediating the depressor response elicited by the greater splanchnic nerve (GSPL) afferent stimulation was explored in rats anesthetized with urethane and alpha-chloralose. Microinjection of lidocaine, and the glutamate receptor antagonists, kynurenic acid and 2-amino-7-phosphonolieptanoic acid, into the CVLM significantly blocked the depressor response induced by the GSPL afferent stimulation. Electrical stimulation of the GSPL inputs excited 48 of 75 CVLM neurons tested (64%). Sixteen out of 21 excited CVLM neurons tested received baroreceptor inputs. Coherence analysis revealed a strong cardiac-related rhythm in the discharges of 11 out of these 21 excited neurons. These results suggest the involvement of CVLM neurons and activation of glutamate receptors in the CVLM in mediating the depressor response induced by the GSPL afferent stimulation in rats.
Peng
Ying-Jie
YJ
Department of Physiology, Medical Center of Fudan University, Shanghai 200032, China. yxp9@po.cwru.edu
Wang
Ning
N
Gong
Qian-Ling
QL
Li
Peng
P
D015763:2-Amino-5-phosphonovalerate / Q000031:analogs & derivatives* / Q000494:pharmacology; D000344:Afferent Pathways / Q000502:physiology; D000818:Animals; D001794:Blood Pressure / Q000502:physiology; D002320:Cardiovascular Physiological Phenomena; D004558:Electric Stimulation; D018691:Excitatory Amino Acid Antagonists / Q000494:pharmacology; D006339:Heart Rate / Q000502:physiology; D007736:Kynurenic Acid / Q000494:pharmacology; D008012:Lidocaine / Q000494:pharmacology; D008297:Male; D008526:Medulla Oblongata / Q000502:physiology*; D011311:Pressoreceptors / Q000502:physiology; D051381:Rats; D017207:Rats, Sprague-Dawley; D017470:Receptors, Glutamate / Q000187:drug effects; D013153:Splanchnic Nerves / Q000502:physiology*
D018691:Excitatory Amino Acid Antagonists; D017470:Receptors, Glutamate; D015763:2-Amino-5-phosphonovalerate; D008012:Lidocaine; D007736:Kynurenic Acid; C031231:2-amino-7-phosphonoheptanoic acid