CL316,243, a β3-adrenergic receptor agonist, induces muscle hypertrophy and increased strength.

Studies in vitro have demonstrated that β3-adrenergic receptors (β3-ARs) regulate protein metabolism in skeletal muscle by promoting protein synthesis and inhibiting protein degradation. In this study, we evaluated whether activation of β3-ARs by the selective agonist CL316,243 modifies the functional and structural properties of skeletal muscles of healthy mice. Daily injections of CL316,243 for 15 days resulted in a significant improvement in muscle force production, assessed by grip strength and weight tests, and an increased myofiber cross-sectional area, indicative of muscle hypertrophy.

Role of hippocampus in polymodal-cue guided tasks in rats.

To examine how signals from different sensory modalities are integrated to generate an appropriate goal-oriented behavior, we trained rats in an eight-arm radial maze to visit a cue arm provided with intramaze cues from different sensory modalities, i.e. visual, tactile and auditory, in order to obtain a reward.

Glucose deprivation promotes activation of mTOR signaling pathway and protein synthesis in rat skeletal muscle cells.

Signaling through mammalian target of rapamycin (mTOR) has been shown to play a central role in the regulation of skeletal muscle growth induced by a wide range of stimuli either mechanical or metabolic, such as growth factors and amino acids. Here, we demonstrate that mTOR and its downstream target, the ribosomal S6 kinase (p70(S6K)), are activated in L6 myocytes by a short-term glucose deprivation. Such response is specific of skeletal muscle and is likely responsible for the increased rate of protein synthesis and expression of the muscle-specific proteins during recovery from glucose deprivation.

CL316,243, a selective β3-adrenoceptor agonist, activates protein translation through mTOR/p70S6K signaling pathway in rat skeletal muscle cells.

Functional β3-adrenoceptors have been found in skeletal muscle where they mediate metabolic oxidation and glucose utilization. Whether β3-adrenoceptors (ARs) also play any role in muscle protein metabolism still remains uncertain. By using rat L6 myocyte cultures, we found that CL316,243, a β3-AR selective agonist, at the concentration of 10(-6) M for 24 h, induced a significant increase of skeletal muscle constitutive proteins such as H- and L-myosin and β-actin.

Validation of a two-compartment model of ventilation/perfusion distribution.

Ventilation (V (A)) to perfusion (Q ) heterogeneity (V (A)/Q ) analyses by a two-compartment lung model (2C), utilizing routine gas exchange measurements and a computer solution to account for O(2) and CO(2) measurements, were compared with multiple inert gas elimination technique (MIGET) analyses and a multi-compartment (MC) model. The 2C and MC estimates of V (A)/Q mismatch were obtained in 10 healthy subjects, 43 patients having chronic obstructive pulmonary disease (COPD) and in 14 dog experiments where hemodynamics and acid-base status were manipulated with gas mixtures, fluid loading and tilt-table stressors. MIGET comparisons with 2C were made on 6 patients and 32 measurements in healthy subjects before and after exercise at normoxia and altitude hypoxia.

Body temperature, autonomic responses, and acute mountain sickness.

A few studies have reported increased body temperature (T(o)) associated with acute mountain sickness (AMS), but these usually include exercise, varying environmental conditions over days, and pulmonary edema. We wished to determine whether T(o) would increase with AMS during early exposure to simulated altitude at rest. Ninety-four exposures of 51 men and women to reduced P(B) (423 mmHg = 16,000 ft = 4850 m) were carried out for 8 to 12 h.