Interactions of peripheral inputs to the motoneuron of the kitten fetus as young as 3 weeks prenatal were studied by reflex discharge from the ventral root as well as by recording from single motoneurons. Facilitation was found between two synergists in fetuses I to 2 weeks before birth. Intracellular recording showed that the facilitation could be explained by summation of excitatory postsynap...

During prolonged low-level contractions, synergist muscles are activated in an alternating pattern of activity and silence called as alternate muscle activity. Resting muscle stiffness is considered to increase due to muscle fatigue. Thus, we investigated whether the difference in the extent of fatigue of each plantar flexor synergist corresponded to the difference in the frequency of alternate...

The study examined the hypothesis that altered synergistic activation of the knee extensors leads to cyclic modulation of the force fluctuations. To test this hypothesis, the force fluctuations were investigated during sustained knee extension at 2.5% of maximal voluntary contraction force for 60 min in 11 men. Surface electromyograms (EMG) were recorded from the rectus femoris (RF), vastus lat...

Previous studies suggest that fast-twitch skeletal muscle overloaded by surgical removal of synergists contains a greater percent of slow-twitch fibers than normal muscle. Therefore we examined subcellular systems known to represent biochemical properties of slow-twitch skeletal muscle by measuring myosin ATPase, Ca2+ regulation of myofibril ATPase, Ca2+ uptake of sarcoplasmic reticulum (SR), a...

The interrelationship of several physiological receptors which influence the hydroosmotic response of the toad urinary bladder was studied employing neurohypophyseal peptides, prostaglandin E(1), theophylline, and cyclic nucleotides. The binding property of agonists (pD(2)), synergists (pS(2)), competitive antagonists (pA(2)), and noncompetitive antagonists (pD(2)') was determined after a suita...

Beet armyworm, Spodoptera exigua (Hübner) is one of the most destructive pests that causes significant losses in crops. Unfortunately, S. exigua have developed resistance toward the majority of insecticides. Synergists may provide an important choice to deal with the resistance problems. Dodecyl dimethyl benzyl ammonium chloride (DDBAC) is a cationic surfactant, which displayed enhancement effe...

During the process of compensatory muscle hypertrophy, satellite cells are thought to proliferate, differentiate, and then fuse with existing myofibers. We hypothesized that early in this process changes occur in the expression of cellular markers indicative of the onset of myogenic processes. The plantaris muscles of rats were overloaded via the unilateral ablation of synergists. Groups of rat...

The aim of this study was to identify spinal target cells of spinocerebellar neurons, in particular the ventral spinocerebellar tract (VSCT) neurons, giving off axon collaterals terminating within the lumbosacral enlargement. Axons of spinocerebellar neurons were stimulated within the cerebellum while searching for most direct synaptic actions on intracellularly recorded hindlimb motoneurons an...

The purpose of this study was to investigate the recruitment pattern of deep and superficial neck flexors evoked by three different cervical flexion exercises using muscle functional MRI. In 19 healthy participants, transverse relaxation time (T2) values were calculated for the longus colli (Lco), longus capitis (Lca), and sternocleidomastoid (SCM) at rest and following three exercises: convent...