ABSTRACT
Any developmental disorder in enteric nervous system [ENS] may lead to congenital motility diseases of the gastrointestinal tract. The present study aimed to examine the structural differentiation and functional activity of the ENS in the Chick embryo. Ten Chick embryos were sacrificed at embryonic day 19 and then, their jejunum and colon specimens were collected. The isolated rings of the intestine were prepared and their motor activity was tested in an organ bath system. The contraction of the tissues was recorded in basic condition and following the stimulation by cholinergic and adrenergic agonists as well as the stimulation of the non-adrenergic-non-cholinergic system by electrical field stimulation [EFS]. The structure of the intestinal specimen was assessed immuno- 1histochemically [IHC] using glial fibrillary acidic protein [GFAP] biomarker. Spontaneous rhythmic contractions were seen in both jejunum and colon specimens. Cholinergic stimulations significantly increased the amplitude of contractions in jejunum [p<0.01] and colon [p<0.001] tissues. However, adrenergic stimulation decreased significantly the amplitude of contractions in isolated tissues prepared from the jejunum [p<0.05] and colon [p<0.001]. The EFS-induced decreases significantly the tension of isolated tissues pre-contracted with potassium chloride in both jejunum [p<0.001] and colon [p<0.001]. The results of IHC were showed a positive immunoreactivity of enteric nervous ganglia with GFAPbiomarker. It seems that the ENS in chick intestine is fully differentiated before birth and it can control the intestinal motility patterns in birds
ABSTRACT
In new prospect of motor control, the effect of muscle force is considered important not only in producing movement but also in inducing stability and control of activity. The aim of present study was to evaluate the electrical activity of periarthicular shoulder muscles by surface EMG in order to identify the muscular activity during series of static and dynamic pattern of movements. This Quasi experimental study was performed on 30 healthy male and female volunteers with age of 20-30 years and mean age of 23.2 +/- 2.9. The subjects were enrolled into this study by simple non-probability sampling and were exposed to different movement patterns randomly. During the experiment the surface EMG of every muscle was recorded. The external load applied to shoulder was assessed at three levels in static as well as dynamic situations. According to the results of this study, increasing the external load on the scapulothoracic muscles caused a significant increase in the activity of the muscles; except for upper trapezious muscle in descending phase of the movement [p<0.05]. After increasing the external load on shoulder in ascending phase, most of the investigated muscles showed significant differences in their activities. [p<0.05]. In static situation by application of external load only teres major muscle showed significant difference in its activity compared to the reference position [p=0.01]. It can be concluded that application of external load during ascending phase of push up is more effective than its application during descending phase. It can be claimed that during ascending phase slight increase in external load as low as 2% of body weight, would induce more alterations in muscular activity compared to higher external load such as 4% of body weight, but in static situation no significant change could be detected
Subject(s)
Humans , Male , Female , Muscles/physiology , Motor Activity , Weight-Bearing , Shoulder/physiologyABSTRACT
The aim of this study was to determine the effect of onesession of whole body vibration training on isokinetic strength of rotator cuff and shoulder proprioception 32 students experienced three positions including control [no vibration], push up with straight elbow and push up with semi flexed elbow [two vibration positions] for 2 minutes with 30 minutes interval between positions. After control position, vibration positions were tested on a random basis by means of a power plate device [Freq: 30Hz and Amp: low]. The isokinetic strength of rotator cuff and shoulder proprioception were measured in angle repositioning test in 3 target angles of 0°, 45° and 90° by means of Kin-Com dynamometer before and after each position. Then the results of 3 positions were compared with one another. Despite decreased dynamic strength of medial rotators after 3 positions, this decrease was significantly less in push up with straight elbow than that in control position [p=0.03]. Also there was a significant difference in concentric MPT of lateral rotators between 3 positions so that, control position caused the greatest decline in lateral rotators strength [p=0.01] and push up with straight elbow was more effective than push up with semi flexed elbow [p=0.03]. Moreover, There was a significant improvement in angle repositioning in 3 positions but only in zero degree a significant difference was detected between the push up with semi flexed elbow position and the control position [p=0.03]. No significant change in muscle strength was found between push up with straight elbow and semi flexed elbow positions. Conclusions: The results of this experiment show that a two minute single-session of whole body vibration is relatively a good stimulation for neuromuscular system in young and healthy individuals