Analysis of the cardiovascular changes evoked by microinjection of NaCl into the nucleus tractus solitarii of rats: evidence for a Na+/Ca2+ relationship.
The effect of various ionic solutions microinjected into the nucleus tractus solitarii (NTS) on blood pressure, heart rate and respiration rate was investigated in urethane-anesthetized rats. Unilateral microinjection of solutions containing NaCl (154 mM), NaCl (154 mM) and KCl (2.8 mM) or NaNO3 (154 mM) into a restricted area of the NTS evoked acute decreases in blood pressure, heart rate and respiration rate. However, calcium chloride (0.36-3.3 mM), present in the microinjection solutions, reduced the decrease in all 3 recorded parameters in a concentration-dependent manner. A disturbance in the Na+/Ca2+ ionic ratio may account for the changes evoked by the administered solutions. These results indicate the presence of a restricted area in the NTS which is sensitive to changes in some vegetative functions.
Lukovic
L
L
Institute of Experimental Pharmacology, Centre of Physiological Sciences, SAS, Bratislava, Czechoslovakia.
de Jong
W
W
D000818:Animals; D001794:Blood Pressure / Q000187:drug effects; D002118:Calcium / Q000378:metabolism / Q000502:physiology*; D002320:Cardiovascular Physiological Phenomena; D002319:Cardiovascular System / Q000187:drug effects*; D006339:Heart Rate / Q000187:drug effects; D008297:Male; D008526:Medulla Oblongata / Q000187:drug effects / Q000502:physiology*; D051381:Rats; D011919:Rats, Inbred Strains; D012119:Respiration / Q000187:drug effects; D012965:Sodium Chloride / Q000494:pharmacology*
D012965:Sodium Chloride; D002118:Calcium