Salivary nitric oxide and alpha-amylase as indexes of training intensity and load

This study examined the variation in salivary nitric oxide (NO), alpha-amylase (sAA) and serum markers of muscle injury during 21 weeks of training in elite swimmers. Samples of saliva and blood were collected once a month during 5 months from 11 male professional athletes during their regular training season. The variation in each marker throughout the 21 weeks was compared with the dynamics of training volume, intensity and load. Unstimulated whole saliva was assessed for NO and sAA whereas venous blood was assessed for lactate dehydrogenase, creatine kinase, and γ-glutamyltransferase. Nitric oxide and sAA showed a proportional response to the intensity of training. However, whereas the concentration of NO increased across the 21 weeks, the activity of sAA decreased. Similar variations in the concentration of NO and the markers of muscle injury were also observed. The higher concentration of NO might be attributed to changes in haemodynamics and muscle regenerative processes. On the other hand, autonomic regulation towards parasympathetic predominance might have been responsible for the decrease in sAA activity. These findings provide appealing evidence for the utilization of salivary constituents in sports medicine to monitor training programmes.

Response of salivary markers of autonomic activity to elite competition

We investigated the response of salivary total protein (TP), alpha-amylase (sAA) and chromogranin A (CgA) to sporting competition and their relation with positive and negative affect. 11 professional swimmers were examined during the first day of a national contest and on a recreated event that matched time-of-the-day and day-of-the-week assessments 2 weeks later. Total protein was determined by the Bradford method and sAA and CgA by Western blotting upon awakening, 30 and 60 min post awakening, immediately before warming up for competition and 5, 20 and 60 min after competition. Psychometric instruments included the Positive Affect and Negative Affect Schedule-X. The concentrations of TP, sAA and CgA differed from controls only prior to and 5 min after the event. We observed positive correlations between higher negative affect scores with higher levels of TP, sAA and CgA prior to the event on the competition day. All 3 markers showed a similar reactivity to sporting competition, which may be attributed to the mechanisms responsible for protein secretion into saliva when collection is performed with no exogenous stimulation. TP is an attractive marker in sports psychology since its determination is faster and cheaper than traditional kinetic or immune assays.

Down-modulation of nitric oxide production in murine macrophages treated with crude plant extracts from the Brazilian Cerrado

Several plant species from the Cerrado biome in Brazil are popularly used as herbal medicines for its reputed analgesic, anti-acid, anti-microbial, anti-inflammatory and anti-tumoral properties, among others. It has been reported that some plant extracts interfere in the production of nitric oxide (NO), an important inflammatory mediator. In the present study, we investigated the effect of hexanic and ethanolic extracts from three plant species on NO production by LPS/IFN-gamma-activated J774 macrophages based on traditional use. The cytotoxic effect of the crude extracts was determined by the thiazolyl blue test (MTT) to measure cell viability. Serjania lethalis stem extracts and Cupania vernalis leaf extracts significantly inhibited NO production, while extracts from Casearia sylvestris var. lingua were inactive or showed low activity on NO production, or were very cytotoxic. The ethanolic stem bark and leaf extracts of Serjania lethalis and Cupania vernalis, respectively, almost completely inhibited the production of NO by J774 macrophages. It can be concluded that the selected extracts are potential sources of active compounds that might be used as anti-inflammatory agents.

The light chain composition of chicken brain myosin-Va: calmodulin, myosin-II essential light chains, and 8-kDa dynein light chain/PIN

Class V myosins are a ubiquitously expressed family of actin-based molecular motors. Biochemical studies on myosin-Va from chick brain indicate that this myosin is a two-headed motor with multiple calmodulin light chains associated with the regulatory or neck domain of each heavy chain, a feature consistent with the regulatory effects of Ca(2+) on this myosin. In this study, the identity of three additional low molecular weight proteins of 23-,17-, and 10 kDa associated with myosin-Va is established. The 23- and 17-kDa subunits are both members of the myosin-II essential light chain gene family, encoded by the chicken L23 and L17 light chain genes, respectively. The 10-kDa subunit is a protein originally identified as a light chain (DLC8) of flagellar and axonemal dynein. The 10-kDa subunit is associated with the tail domain of myosin-Va.

Localization of unconventional myosins V and VI in neuronal growth cones

Class V and VI myosins, two of the six known classes of actin-based motor genes expressed in vertebrate brain (Class I, II, V, VI, IX, and XV), have been suggested to be organelle motors. In this report, the neuronal expression and subcellular localization of chicken brain myosin V and myosin VI is examined. Both myosins are expressed in brain during embryogenesis. In cultured dorsal root ganglion (DRG) neurons, immunolocalization of myosin V and myosin VI revealed a similar distribution for these two myosins. Both are present within cell bodies, neurites and growth cones. Both of these myosins exhibit punctate labeling patterns that are found in the same subcellular region as microtubules in growth cone central domains. In peripheral growth cone domains, where individual puncta are more readily resolved, we observe a similar number of myosin V and myosin VI puncta. However, less than 20% of myosin V and myosin VI puncta colocalize with each other in the peripheral domains. After live cell extraction, punctate staining of myosin V and myosin VI is reduced in peripheral domains. However, we do not detect such changes in the central domains, suggesting that these myosins are associated with cytoskeletal/organelle structures. In peripheral growth cone domains myosin VI exhibits a higher extractability than myosin V. This difference between myosin V and VI was also found in a biochemical growth cone particle preparation from brain, suggesting that a significant portion of these two motors has a distinct subcellular distribution.

Biochemical and immunological characterization of p190-calmodulin complex from vertebrate brain: a novel calmodulin-binding myosin

We have recently identified a novel 190-kD calmodulin-binding protein (p190) associated with the actin-based cytoskeleton from mammalian brain (Larson, R. E., D. E. Pitta, and J. A. Ferro. 1988. Braz. J. Med. Biol. Res. 21:213-217; Larson, R. E., F. S. Espindola, and E. M. Espreafico. 1990. J. Neurochem. 54:1288-1294). These studies indicated that p190 is a phosphoprotein substrate for calmodulin-dependent kinase II and has calcium- and calmodulin-stimulated MgATPase activity. We now have biochemical and immunological evidence that this protein is a novel calmodulin-binding myosin whose properties include (a) Ca2+ dependent action activation of its Mg-ATPase activity, which seems to be mediated by Ca2+ binding directly to calmodulin(s) associated with p190 (maximal activation by actin requires the presence of Ca2+ and is further augmented by addition of exogenous calmodulin); (b) ATP-sensitive cross-linking of skeletal muscle F-actin, as demonstrated by the low-speed actin sedimentation assay; and (c) cross-reactivity with mAbs specific for epitopes in the head of brush border myosin I. We also show that p190 has properties distinct from conventional brain myosin II and brush border myosin I, including (a) separation of p190 from brain myosin II by gel filtration on a Sephacryl S-500 column; (b) lack by p190 of K(+)-stimulated EDTA ATPase activity characteristic of most myosins; (c) lack of immunological cross-reactivity of polyclonal antibodies which recognize p190 and brain myosin II, respectively; (d) lack of immunological recognition of p190 by mAbs against an epitope in the tail region of brush border myosin I; and (e) distinctive proteolytic susceptibility to calpain. A survey of rat tissues by immunoblotting indicated that p190 is expressed predominantly in the adult forebrain and cerebellum, and could be detected in embryos 11 d post coitus. Immunocytochemical studies showed p190 to be present in the perikarya and dendritic extensions of Purkinje cells of the cerebellum.

Calmodulin-binding proteins and calcium/calmodulin-regulated enzyme activities associated with brain actomyosin

Calcium- and calmodulin-regulated ATPase and protein kinase activities are shown to be strongly associated with brain actomyosin. Similar enzymatic activities and an invariable polypeptide profile on sodium dodecyl sulfate-polyacrylamide gel electrophoresis were obtained for brain actomyosin taken through a solubilization-precipitation cycle (1.0-0.1 M KCl), or precipitated from buffers containing 1% Triton X-100 or 10 mM EDTA and 10 mM EGTA. These data suggest a specific complex of brain actomyosin with a protein kinase similar to calmodulin-dependent kinase II, a 190-kDa calmodulin-binding protein (P190), and a calmodulin-like polypeptide. P190 was the major substrate for endogenous calcium-dependent phosphorylation. 125I-Calmodulin overlay technique revealed four major calmodulin-binding polypeptides associated with brain actomyosin: 50- and 60-kDa subunits of the calmodulin-dependent kinase II, P190, and a high molecular weight polypeptide which is probably fodrin. A fraction enriched in P190 had Ca2(+)- and calmodulin-stimulated MgATPase activity, but not myosin-like K-EDTA ATPase activity. The lack of immunological cross-reactivity between brain myosin heavy chain and P190 confirmed that they are distinct molecules.