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Cardiorespiratory effects of intravenous N ‐methyl‐ D ‐aspartate challenge in anaesthetized rats
Author(s) -
Kaczyńska Katarzyna,
SzeredaPrzestaszewska Ma?gorzata
Publication year - 2004
Publication title -
clinical and experimental pharmacology and physiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.752
H-Index - 103
eISSN - 1440-1681
pISSN - 0305-1870
DOI - 10.1111/j.1440-1681.2004.03958.x
Subject(s) - nmda receptor , respiratory system , chloralose , respiratory rate , anesthesia , vagotomy , tidal volume , medicine , heart rate , blood pressure , bolus (digestion) , ventilation (architecture) , receptor , mechanical engineering , engineering
Summary 1. Experiments were performed to determine the effects of systemic application of N ‐methyl‐ d ‐aspartate (NMDA) on respiratory variables and blood pressure in 22 urethane/chloralose‐anaesthetized, spontaneously breathing rats. 2. Bolus injection of NMDA at a dose of 27 µmol/kg, i.v., in neurally intact rats evoked a depression of breathing, most apparent at 30 s, comprising a decrease in tidal volume ( P < 0.001) and respiratory rate ( P < 0.001). The expiratory apnoea appeared in three intact rats only. 3. The respiratory effects of NMDA were independent of the vagal integrity between lungs and the nodose ganglia. Elimination of supranodose connection to the medulla reduced the prolongation of the expiratory time ( P < 0.01). 4. N ‐Methyl‐ d ‐aspartate induced an initial rise in blood pressure followed by hypotension in rats treated by infra‐ and supranodose vagotomy. 5. It is concluded that the respiratory response to systemic NMDA challenge occurs beyond lung vagi and indicates that neurons of the nodose ganglia contribute to NMDA inhibition of the expiratory time.