Intracerebroventricular physostigmine enhances blood pressure and heat loss in running rats

The aim of this study was to evaluate the effects of the stimulation of central cholinergic synapses in the regulation of heat loss in untrained rats during exercise. The animals were separated into two groups (exercise or rest) and tail skin temperature (T(tail)), core temperature and blood pressur...

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Bibliographic Details
Published in:Journal of physiology and pharmacology : an official journal of the Polish Physiological Society 2007-03, Vol.58 (1), p.3-17
Main Authors: Pires, W, Wanner, S P, La Guardia, R B, Rodrigues, L O C, Silveira, S A, Coimbra, C C, Marubayashi, U, Lima, N R V
Format: Article
Language:English
Subjects:
Acetylcholine - metabolism
Animals
Area Under Curve
Blood Pressure - drug effects
Body Temperature Regulation - drug effects
Brain - cytology
Brain - drug effects
Brain - metabolism
Cholinesterase Inhibitors - administration & dosage
Cholinesterase Inhibitors - pharmacology
Injections, Intraventricular
Male
Neurons - drug effects
Neurons - metabolism
Physical Conditioning, Animal
Physical Exertion - physiology
Physostigmine - administration & dosage
Physostigmine - pharmacology
Rats
Rats, Wistar
Running
Skin Temperature - drug effects
Synaptic Transmission - drug effects
Telemetry
Time Factors
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Summary:The aim of this study was to evaluate the effects of the stimulation of central cholinergic synapses in the regulation of heat loss in untrained rats during exercise. The animals were separated into two groups (exercise or rest) and tail skin temperature (T(tail)), core temperature and blood pressure were measured after injection of 2 microL of 5x10(-3) M physostigmine (Phy; n = 8) or 0.15 M NaCl solution (Sal; n = 8) into the lateral cerebral ventricle. Blood pressure was recorded by a catheter implanted into the abdominal aorta, T(tail) was measured using a thermistor taped to the tail and intraperitoneal temperature (T(b)) was recorded by telemetry. During exercise, Phy-treated rats had a higher increase in mean blood pressure (147 +/- 4 mmHg Phy vs. 121 +/- 3 mmHg Sal; P < 0.001) and higher T(tail) (26.4 +/- 1.0 degrees C Phy vs. 23.8 +/- 0.5 degrees C Sal; P < 0.05) that was closely related to the increase in systolic arterial pressure (r = 0.83; P < 0.001). In addition, Phy injection attenuated the exercise-induced increase in T(b) compared with controls without affecting running time. We conclude that the activation of central cholinergic synapses during exercise increases heat dissipation due to the higher increase in blood pressure.
ISSN:0867-5910