Interactions of temperature and angiotensin II in paraventricular neurons of rats in vitro.
We recorded extracellular impulse activity of hypothalamic paraventricular neurons ( n=75) in rat brain slices during application of angiotensin II (ANG II, 10(-9)-10(-6) M) and/or temperature changes (32-42 degrees C). ANG II, with a threshold concentration of 10(-8) M, increased the firing rate in more than 80% of the neurons with strongest excitations occurring in bursting neurons. Increasing the temperature also raised the discharge rate in the majority of the neurons, often together with enhanced burst discharges. When ANG II was applied during ongoing sinusoidal temperature changes, its effects were more pronounced at elevated temperatures. These electrophysiological data illustrate that stimulus-encoding properties at the neuronal level can contribute to the interactions between osmoregulatory and thermoregulatory mechanisms including mutual sensitization when different stimuli (here: ANG II and temperature changes) are applied simultaneously.
Dewald
Mathias
M
Institut für Normale und Pathologische Physiologie, Deutschhausstrasse 2, 35037 Marburg, Germany.
Braun
Hans A
HA
Huber
Martin T
MT
Zwingmann
Detlev
D
Roth
Joachim
J
Voigt
Karlheinz
K
D000804:Angiotensin II / Q000494:pharmacology*; D000818:Animals; D001833:Body Temperature Regulation / Q000502:physiology; D004558:Electric Stimulation; D004594:Electrophysiology; D066298:In Vitro Techniques; D008297:Male; D009474:Neurons / Q000187:drug effects* / Q000502:physiology*; D009489:Neurosecretion / Q000187:drug effects; D010286:Paraventricular Hypothalamic Nucleus / Q000166:cytology / Q000187:drug effects / Q000502:physiology*; D018408:Patch-Clamp Techniques; D051381:Rats; D017207:Rats, Sprague-Dawley; D013696:Temperature; D014882:Water-Electrolyte Balance / Q000502:physiology
D000804:Angiotensin II