Effects of adequate vestibular stimulation on locomotor activity in the guinea pig fore- and hindlimb muscles. Tilting around a transverse axis

1988 ◽  
Vol 19 (6) ◽  
pp. 613-617
Author(s):  
V. V. Marlinskii ◽  
F. I. Tsintsabadze
Keyword(s):  
Locomotor Activity ◽  
Guinea Pig ◽  
Vestibular Stimulation ◽  
Transverse Axis ◽  
Hindlimb Muscles

Guinea pig soleus and gastrocnemius electromyograms at varying speeds, grades, and loads

1982 ◽  
Vol 52 (2) ◽  
pp. 451-457 ◽  
Author(s):  
K. R. Gardiner ◽  
P. F. Gardiner ◽  
V. R. Edgerton
Keyword(s):  
Guinea Pig ◽  
Work Load ◽  
Burst Duration ◽  
Lateral Gastrocnemius ◽  
Biochemical Alterations ◽  
Hindlimb Muscles ◽  
Slow Twitch ◽  
Fast Twitch ◽  
Grade Increase ◽  
Emg Electrodes

The purpose of the study was to describe changes that occur in the usage of fast-twitch and slow-twitch guinea pig hindlimb muscles, as estimated using chronically implanted electromyogram (EMG) electrodes, during voluntary locomotion under various conditions. Guinea pigs, in which fine wire electrodes were implanted in soleus (SOL) and lateral gastrocnemius (LG) muscles, were exercised at various speeds (13.4, 26.8, 40.2 m/min), grades (0–30%) and in some conditions loads (50–150 g) on a motor-driven treadmill. Bipolar EMG signals were rectified-averaged (RA-EMG) and analyzed for burst duration, amplitude, and the integral of each burst (IEMG). For each condition and muscle, total IEMG/min (IEMG/step x steps/min) was calculated and expressed as a percent of the maximum IEMG recorded. With increasing speed at 0% grade, the ratio of LG to SOL IEMG, each expressed as percent of maximum, remained constant at about 0.82. An increased stepping rate of 150 (at 13.4 m/min) to 225 (at 40.2 m/min) steps/min was accompanied by a 37% decrease in burst duration in LG and SOL. When the treadmill belt speed was increased from 13.4 to 4.02 m/min at 30% grade, the LG/SOL ratio increased from 0.83 to 1.03, whereas burst duration decreased by 49% (SOL) and 51% (LG). Soleus IEMG did not change significantly with increases in speed or grade; LG IEMG increased significantly with speed at 10% grade and with grade increase at the highest speed (40.2 m/min). These data provide some insight into how modifications of work load on a treadmill affect overall muscle activity and may assist in the interpretation of training-induced muscle biochemical alterations previously noted by other investigators.

Properties of immobilized guinea pig hindlimb muscles

1976 ◽  
Vol 231 (5) ◽  
pp. 1520-1526 ◽  
Author(s):  
A Maier ◽  
JL Crockett ◽  
DR Simpson ◽  
IV Saubert CW ◽  
VR Edgerton
Keyword(s):  
Guinea Pig ◽  
Chloral Hydrate ◽  
Myofibrillar Protein ◽  
Contractile Properties ◽  
Specific Factor ◽  
Normal Muscle ◽  
Muscle Weight ◽  
Time To Peak ◽  
Hindlimb Muscles ◽  
Tetanic Tension

Guinea pig hindlimbs were unilaterally immobilized at resting length to evaluate histochemical, biochemical, and contractile properties of immobilized muscle. Contralateral limbs remained unrestrained. Four weeks later contractile properties were measured under chloral hydrate anesthesia. Average time-to-peak tension of the immobilized soleus was 30% less, whereas that of the gastrocnemius was not significantly changed relative to contralateral muscles. Immobilized soleus muscles acquired as much as 25% fibers with high alkaline myofibrillar adenosine triphosphatase activity; these fibers do not occur in the normal muscle. Neither the immobilized soleus nor gastrocnemius fatigued more quickly than their contralateral counterparts. In the immobilized gastrocnemius myofibrillar protein (mg/g muscle) decreased to 76% and maximum tetanic tension to 70% of contralateral values. However, tetanic tension per gram wet muscle weight or 100 mg myofibrillar protein was significantly greater in the immobilized gastrocnemius. No specific factor responsible for the increased tetanic tension could be identified.

Sign in / Sign up

Export Citation Format

Share Document