Heart rate, blood pressure, and running speed responses to mesencephalic locomotor region stimulation in anesthetized rats

Kwong Yew Raymond Chong, Toby G. Bedford

Research output: Contribution to journalArticle

18 Citations (Scopus)

Abstract

The decerebrate rat locomotor preparation described in a previous study requires extensive brain surgery with the possibility of significant blood loss. The purpose of this study was to improve on the previous model by using lightly anesthetized instead of decerebrated rats. After initial surgery consisting of boring a small hole through the parietal bone, the animals were maintained on low levels of halothane anesthetic. The mesencephalic locomotor region was then located by physiological criteria using stereotaxic coordinates from the previous study. Locomotor speed, blood pressure and heart rate responses were then measured over a wide range of stimulation currents that elicited a maximal running speed. Stimulation currents ranged from 36 μA for walking to 82 μA for fast galloping. Locomotor speeds ranged from 20 m/min for walking to 64 m/min for fast galloping. Some animals easily achieved galloping speeds beyond 100 m/min. Blood pressure and heart rate increased with increasing stimulation currents. Blood pressure also increased during stimulation after muscular paralysis. This was not due to current spread, suggesting that the mesencephalic locomotor region might be involved in central command mechanisms. Heart rate did not increase after paralysis. This supports other multipoint dynamic studies suggesting that movement per se may be necessary to induce heart rate changes, presumably via joint mechanoreceptors. The range of locomotor patterns and cardiovascular responses were obtained under self-supported conditions. By defining the mesencephalic locomotor region via physiological criteria, and by grouping blood pressure and heart rate measurements by gait rather than by stimulation currents, the potential use of the intact model for cardiovascular control studies was demonstrated. The animals were able to run and gallop at high speeds considering they were anesthetized. The simplified preparation will be useful for more complex cardiovascular experiments requiring intact and self-supported conditions.

Original languageEnglish (US)
Pages (from-to)280-284
Number of pages5
JournalPflugers Archiv European Journal of Physiology
Volume434
Issue number3
DOIs
StatePublished - Jul 14 1997
Externally publishedYes

Fingerprint

Blood pressure
Running
Rats
Heart Rate
Blood Pressure
Animals
Paralysis
Surgery
Walking
Cardiovascular Models
Parietal Bone
Mechanoreceptors
Boring
Halothane
Gait
Anesthetics
Brain
Bone
Blood
Joints

Keywords

  • Anesthesia
  • Cardiovascular responses
  • Central command
  • Dynamic exercise
  • Feedforward control
  • Mesencephalic locomotor region
  • MLR
  • Pedunculopontine tegmental nucleus

ASJC Scopus subject areas

  • Physiology

Cite this

@article{575e997ee1ae44da82ff2bde53842a95,
title = "Heart rate, blood pressure, and running speed responses to mesencephalic locomotor region stimulation in anesthetized rats",
abstract = "The decerebrate rat locomotor preparation described in a previous study requires extensive brain surgery with the possibility of significant blood loss. The purpose of this study was to improve on the previous model by using lightly anesthetized instead of decerebrated rats. After initial surgery consisting of boring a small hole through the parietal bone, the animals were maintained on low levels of halothane anesthetic. The mesencephalic locomotor region was then located by physiological criteria using stereotaxic coordinates from the previous study. Locomotor speed, blood pressure and heart rate responses were then measured over a wide range of stimulation currents that elicited a maximal running speed. Stimulation currents ranged from 36 μA for walking to 82 μA for fast galloping. Locomotor speeds ranged from 20 m/min for walking to 64 m/min for fast galloping. Some animals easily achieved galloping speeds beyond 100 m/min. Blood pressure and heart rate increased with increasing stimulation currents. Blood pressure also increased during stimulation after muscular paralysis. This was not due to current spread, suggesting that the mesencephalic locomotor region might be involved in central command mechanisms. Heart rate did not increase after paralysis. This supports other multipoint dynamic studies suggesting that movement per se may be necessary to induce heart rate changes, presumably via joint mechanoreceptors. The range of locomotor patterns and cardiovascular responses were obtained under self-supported conditions. By defining the mesencephalic locomotor region via physiological criteria, and by grouping blood pressure and heart rate measurements by gait rather than by stimulation currents, the potential use of the intact model for cardiovascular control studies was demonstrated. The animals were able to run and gallop at high speeds considering they were anesthetized. The simplified preparation will be useful for more complex cardiovascular experiments requiring intact and self-supported conditions.",
keywords = "Anesthesia, Cardiovascular responses, Central command, Dynamic exercise, Feedforward control, Mesencephalic locomotor region, MLR, Pedunculopontine tegmental nucleus",
author = "Chong, {Kwong Yew Raymond} and Bedford, {Toby G.}",
year = "1997",
month = "7",
day = "14",
doi = "10.1007/s004240050397",
language = "English (US)",
volume = "434",
pages = "280--284",
journal = "Pflugers Archiv European Journal of Physiology",
issn = "0031-6768",
publisher = "Springer Verlag",
number = "3",

}

TY - JOUR

T1 - Heart rate, blood pressure, and running speed responses to mesencephalic locomotor region stimulation in anesthetized rats

AU - Chong, Kwong Yew Raymond

AU - Bedford, Toby G.

PY - 1997/7/14

Y1 - 1997/7/14

N2 - The decerebrate rat locomotor preparation described in a previous study requires extensive brain surgery with the possibility of significant blood loss. The purpose of this study was to improve on the previous model by using lightly anesthetized instead of decerebrated rats. After initial surgery consisting of boring a small hole through the parietal bone, the animals were maintained on low levels of halothane anesthetic. The mesencephalic locomotor region was then located by physiological criteria using stereotaxic coordinates from the previous study. Locomotor speed, blood pressure and heart rate responses were then measured over a wide range of stimulation currents that elicited a maximal running speed. Stimulation currents ranged from 36 μA for walking to 82 μA for fast galloping. Locomotor speeds ranged from 20 m/min for walking to 64 m/min for fast galloping. Some animals easily achieved galloping speeds beyond 100 m/min. Blood pressure and heart rate increased with increasing stimulation currents. Blood pressure also increased during stimulation after muscular paralysis. This was not due to current spread, suggesting that the mesencephalic locomotor region might be involved in central command mechanisms. Heart rate did not increase after paralysis. This supports other multipoint dynamic studies suggesting that movement per se may be necessary to induce heart rate changes, presumably via joint mechanoreceptors. The range of locomotor patterns and cardiovascular responses were obtained under self-supported conditions. By defining the mesencephalic locomotor region via physiological criteria, and by grouping blood pressure and heart rate measurements by gait rather than by stimulation currents, the potential use of the intact model for cardiovascular control studies was demonstrated. The animals were able to run and gallop at high speeds considering they were anesthetized. The simplified preparation will be useful for more complex cardiovascular experiments requiring intact and self-supported conditions.

AB - The decerebrate rat locomotor preparation described in a previous study requires extensive brain surgery with the possibility of significant blood loss. The purpose of this study was to improve on the previous model by using lightly anesthetized instead of decerebrated rats. After initial surgery consisting of boring a small hole through the parietal bone, the animals were maintained on low levels of halothane anesthetic. The mesencephalic locomotor region was then located by physiological criteria using stereotaxic coordinates from the previous study. Locomotor speed, blood pressure and heart rate responses were then measured over a wide range of stimulation currents that elicited a maximal running speed. Stimulation currents ranged from 36 μA for walking to 82 μA for fast galloping. Locomotor speeds ranged from 20 m/min for walking to 64 m/min for fast galloping. Some animals easily achieved galloping speeds beyond 100 m/min. Blood pressure and heart rate increased with increasing stimulation currents. Blood pressure also increased during stimulation after muscular paralysis. This was not due to current spread, suggesting that the mesencephalic locomotor region might be involved in central command mechanisms. Heart rate did not increase after paralysis. This supports other multipoint dynamic studies suggesting that movement per se may be necessary to induce heart rate changes, presumably via joint mechanoreceptors. The range of locomotor patterns and cardiovascular responses were obtained under self-supported conditions. By defining the mesencephalic locomotor region via physiological criteria, and by grouping blood pressure and heart rate measurements by gait rather than by stimulation currents, the potential use of the intact model for cardiovascular control studies was demonstrated. The animals were able to run and gallop at high speeds considering they were anesthetized. The simplified preparation will be useful for more complex cardiovascular experiments requiring intact and self-supported conditions.

KW - Anesthesia

KW - Cardiovascular responses

KW - Central command

KW - Dynamic exercise

KW - Feedforward control

KW - Mesencephalic locomotor region

KW - MLR

KW - Pedunculopontine tegmental nucleus

UR - http://www.scopus.com/inward/record.url?scp=0030920184&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=0030920184&partnerID=8YFLogxK

U2 - 10.1007/s004240050397

DO - 10.1007/s004240050397

M3 - Article

VL - 434

SP - 280

EP - 284

JO - Pflugers Archiv European Journal of Physiology

JF - Pflugers Archiv European Journal of Physiology

SN - 0031-6768

IS - 3

ER -