TY - JOUR
T1 - Release of substance P in the nucleus tractus solitarius measured by in vivo microdialysis
T2 - response to stimulation of the aortic depressor nerves in rabbit
AU - Morilak, David A.
AU - Morris, Margaret
AU - Chalmers, John
PY - 1988/11/22
Y1 - 1988/11/22
N2 - Substance P (SP) is found in high concentration in the nucleus tractus solitarius (NTS), and is a neurotransmitter candidate in primary baroreceptor afferents to the NTS. Release of SP in the medial NTS of halothane-anesthetized rabbits was measured by in vivo microdialysis. Bilateral electrical stimulation of the aortic depressor nerves (ADN) elicited a significant elevation in SP collected during the period following stimulation, while sham stimulation had no effect. Perfusion through the dialysis probe with a high-potassium (150 mM) solution caused a large increase in the level of SP collected, verifying the neural origin of this release. Possible explanations for the delay in increased release of SP include interaction with carotid afferents, diffusion time, or excitation of SP-containing inputs to the NTS originating elsewhere in the brain. This study demonstrates that SP release in the NTS is elevated by activation of baroreceptor afferents, supporting the hypothesis that SP plays a role in the central integration of cardiovascular control. Whether this relase is from primary afferent terminals, or from another source, remains to be seen.
AB - Substance P (SP) is found in high concentration in the nucleus tractus solitarius (NTS), and is a neurotransmitter candidate in primary baroreceptor afferents to the NTS. Release of SP in the medial NTS of halothane-anesthetized rabbits was measured by in vivo microdialysis. Bilateral electrical stimulation of the aortic depressor nerves (ADN) elicited a significant elevation in SP collected during the period following stimulation, while sham stimulation had no effect. Perfusion through the dialysis probe with a high-potassium (150 mM) solution caused a large increase in the level of SP collected, verifying the neural origin of this release. Possible explanations for the delay in increased release of SP include interaction with carotid afferents, diffusion time, or excitation of SP-containing inputs to the NTS originating elsewhere in the brain. This study demonstrates that SP release in the NTS is elevated by activation of baroreceptor afferents, supporting the hypothesis that SP plays a role in the central integration of cardiovascular control. Whether this relase is from primary afferent terminals, or from another source, remains to be seen.
KW - Aortic depressor nerve
KW - Baroreflex
KW - Microdialysis
KW - Neuropeptide
KW - Neurotransmitter release
KW - Nucleus tractus solitarii
KW - Substance P
UR - http://www.scopus.com/inward/record.url?scp=0023816559&partnerID=8YFLogxK
U2 - 10.1016/0304-3940(88)90283-2
DO - 10.1016/0304-3940(88)90283-2
M3 - Article
C2 - 2468113
AN - SCOPUS:0023816559
SN - 0304-3940
VL - 94
SP - 131
EP - 137
JO - Neuroscience letters
JF - Neuroscience letters
IS - 1-2
ER -