TY - JOUR
T1 - A single minute lesion around the ventral respiratory group in medulla produces fatal apnea in cats
AU - Hsieh, J. H.
AU - Chang, Y. C.
AU - Su, C. K.
AU - Hwang, J. C.
AU - Yen, C. T.
AU - Chai, C. Y.
N1 - Funding Information:
The authors express their gratitude to Drs K.K. Wu, T.K. Tang and T.L. Su for their encouragement and support during this study. We thank Mr G.T. Chen for preparation of illustrations and Ms J.J. Pan for preparation of the manuscript. Thanks are due to Drs S.H. Ngai, Columbia University, New York, and C.V. Weaver of Fu Jen Catholic University, Taipei, for comments of this paper. This study was support in part by the Foundation of Biomedical Sciences, Shih-Chun Wang Research Fund and the National Science Council, R.O.C., No. NSC87-2314-B-001-002.
PY - 1998/8/27
Y1 - 1998/8/27
N2 - In 35 adult cats anesthetized with intraperitoneal chloralose and urethane, the ventrolateral medulla was explored by microinjection of kainic acid (KA, 24 mM, 200 nl) with metal electrode-tubing or glass micropipette to determine regions which elicit persistent apnea. Persistent apnea is defined as: (1) In spontaneously breathing cats, termination of respiration over 3 min with a decrease of the mean systemic arterial pressure (MSAP) to 25 mm Hg. (2) In animals under artificial ventilation and paralyzed by gallamine, cessation of bilateral phrenic nerve (PNA) activities over 25 min. The apnea producing area was located dorsal to the rostral pole of the lateral reticular nucleus, ventromedial to the ambiguous nucleus and immediately caudal to the retrofacial nucleus. Functionally, this region includes the rostral part of the ventral respiratory group (rVRG) encompassing the pre-Botzinger area. We define this region as the VRG apnea producing area (VRG-Apa). Fatal apneusis was observed under following conditions: (1) Persistent apnea was produced after a single KA microinjection in one side of the VRG-Apa (5 animals). Microinjection of sodium glutamate (0.25 M, 70-200 nl) in the same area produced only brief apnea, while microinjection of kynurenic acid (0.1 M, 200 nl) showed little effect on the respiration but slightly increased the SAP. (2) Positioning an electrode nearby but not in the VRG-Apa with or without KA injection did not produce apnea. But when a second electrode insertion to the opposite VRG-Apa immediately produced persistent apnea even without KA injection (6 animals). (3) Midsagittal division of the medulla 0-5 mm rostral to the obex produced persistent silence of PNA on both sides in artificial ventilated animals (7 animals), while similar division 0-5 mm caudal to the obex (4 animals) produced a brief but reversible quiescence of PNA. In conclusion, findings of the present study support the existence of a restricted region of VRG-Apa. VRG-Apa on both sides are closely connected, and integrity of both VRG-Apa is essential for normal respiration. Copyright (C) 1998 Elsevier Science B.V.
AB - In 35 adult cats anesthetized with intraperitoneal chloralose and urethane, the ventrolateral medulla was explored by microinjection of kainic acid (KA, 24 mM, 200 nl) with metal electrode-tubing or glass micropipette to determine regions which elicit persistent apnea. Persistent apnea is defined as: (1) In spontaneously breathing cats, termination of respiration over 3 min with a decrease of the mean systemic arterial pressure (MSAP) to 25 mm Hg. (2) In animals under artificial ventilation and paralyzed by gallamine, cessation of bilateral phrenic nerve (PNA) activities over 25 min. The apnea producing area was located dorsal to the rostral pole of the lateral reticular nucleus, ventromedial to the ambiguous nucleus and immediately caudal to the retrofacial nucleus. Functionally, this region includes the rostral part of the ventral respiratory group (rVRG) encompassing the pre-Botzinger area. We define this region as the VRG apnea producing area (VRG-Apa). Fatal apneusis was observed under following conditions: (1) Persistent apnea was produced after a single KA microinjection in one side of the VRG-Apa (5 animals). Microinjection of sodium glutamate (0.25 M, 70-200 nl) in the same area produced only brief apnea, while microinjection of kynurenic acid (0.1 M, 200 nl) showed little effect on the respiration but slightly increased the SAP. (2) Positioning an electrode nearby but not in the VRG-Apa with or without KA injection did not produce apnea. But when a second electrode insertion to the opposite VRG-Apa immediately produced persistent apnea even without KA injection (6 animals). (3) Midsagittal division of the medulla 0-5 mm rostral to the obex produced persistent silence of PNA on both sides in artificial ventilated animals (7 animals), while similar division 0-5 mm caudal to the obex (4 animals) produced a brief but reversible quiescence of PNA. In conclusion, findings of the present study support the existence of a restricted region of VRG-Apa. VRG-Apa on both sides are closely connected, and integrity of both VRG-Apa is essential for normal respiration. Copyright (C) 1998 Elsevier Science B.V.
KW - Apnea
KW - Midsagittal division in medulla
KW - Phrenic nerve activity
KW - Ventral respiratory group
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U2 - 10.1016/S0165-1838(98)00117-9
DO - 10.1016/S0165-1838(98)00117-9
M3 - Article
C2 - 9808366
AN - SCOPUS:0032572732
VL - 73
SP - 7
EP - 18
JO - Journal of the Autonomic Nervous System
JF - Journal of the Autonomic Nervous System
SN - 1566-0702
IS - 1
ER -