Interactive effects of mechano- and chemo-receptor inputs on cardiorespiratory outputs in the toad.
Arterial blood pressure (P(b)), pulmocutaneous blood flow (Q(pc)), heart rate (f(H)), and fictive ventilation (motor activity in the Vth cranial nerve, V(int)), were recorded from decerebrated, paralysed toads receiving unidirectional ventilation with experimental gas mixtures over a range of lung inflation. At the onset of spontaneous bouts of fictive ventilation, (Q(pc)) and P(b) increased immediately, often with changes in heart rate, implying central cardiorespiratory interactions. Inflation of the lungs with different gas mixtures revealed that the effect of hypercarbia on V(int) was reduced by lung inflation and that feedback from pulmonary stretch receptors may summate with central feedforward control of f(H) and (Q(pc)) in an interactive fashion. The results of bolus injections of cyanide into the carotid or the pulmonary circulations suggest there are oxygen sensitive receptors in both circuits that affect the cardiovascular system directly and respiratory activity by complex central interactions with inputs from central chemoreceptors and pulmonary stretch receptors.
Wang
T
T
Biosciences, The University of Birmingham, Edgbaston, UK. tobias.wang@biology.au.dk
Taylor
E W
EW
Reid
S G
SG
Milsom
W K
WK
D000344:Afferent Pathways / Q000502:physiology; D000818:Animals; D001794:Blood Pressure / Q000502:physiology; D002024:Bufo marinus / Q000502:physiology*; D002628:Chemoreceptor Cells / Q000187:drug effects / Q000502:physiology*; D003655:Decerebrate State; D004525:Efferent Pathways / Q000502:physiology; D004791:Enzyme Inhibitors / Q000494:pharmacology; D006339:Heart Rate / Q000502:physiology; D000860:Hypoxia / Q000503:physiopathology*; D008465:Mechanoreceptors / Q000502:physiology*; D011652:Pulmonary Circulation / Q000502:physiology; D012123:Pulmonary Ventilation / Q000187:drug effects / Q000502:physiology; D012121:Respiration, Artificial; D012125:Respiratory Center / Q000502:physiology*; D015656:Respiratory Mechanics / Q000187:drug effects / Q000502:physiology*; D012867:Skin / Q000098:blood supply; D012966:Sodium Cyanide / Q000494:pharmacology
D004791:Enzyme Inhibitors; D012966:Sodium Cyanide