Sound symbolism in manual and vocal responses: phoneme-response interactions associated with grasping as well as vertical and size dimensions of keypresses.

It has been shown that reading the vowel [i] and consonant [t] facilitates precision grip responses, while [ɑ] and [k] are associated with faster power grip responses. A similar effect has been observed when participants perform responses with small or large response keys. The present study investigated whether the vowels and consonants could produce different effects with the grip responses and keypresses when the speech units are read aloud (Experiment 1) or silently (Experiment 2). As a second objective, the study investigated whether the recently observed effect, in which the upper position of a visual stimulus is associated with faster vocalizations of the high vowel and the lower position is associated with the low vowel, can be observed in manual responses linking, for example, the [i] with responses of the upper key and [ɑ] with lower responses. Firstly, the study showed that when the consonants are overtly articulated, the interaction effect can be observed only with the grip responses, while the vowel production was shown to systematically influence small/large keypresses, as well as precision/power grip responses. Secondly, the vowel [i] and consonant [t] were associated with the upper responses, while [ɑ] and [k] were associated with the lower responses, particularly in the overt articulation task. The paper delves into the potential sound-symbolic implications of these phonetic elements, suggesting that their acoustic and articulatory characteristics might implicitly align them with specific response magnitudes, vertical positions, and grip types.

Changes in volatile fatty acid production and microbiome during fermentation of food waste from hospitality sector.

Due to the increasing demand for low carbon-footprint bioproducts in the markets, innovative processes technologies and products are needed. The objective of this study was to assess the quality and potential of food waste (FW) from the hospitality sector to produce volatile fatty acids (VFAs). A batch type acid fermentation system was used to study VFA production in different process conditions (a decreased pH and increased organic loading rate). The evolution of VFAs and long-chain fatty acids was followed. Amplicon sequencing of the 16S rRNA gene was used to investigate the bacterial and archaeal community, and elucidate microbial communities in different FW and process conditions. The results show that high VFA concentrations (of up to 18 g/L) were achieved in overloaded conditions, which were also affected by the activity and composition of the inoculum. FW played an important role in modulating microbial composition, especially the bacterial communities belonging to the lactic acid bacteria group.

The Influence of Number Magnitude on Vocal Responses.

The study investigated whether number magnitude can influence vocal responses. Participants produced either short or long version of the vowel [ɑ] (Experiment 1), or high or low-pitched version of that vowel (Experiment 2), according to the parity of a visually presented number. In addition to measuring reaction times (RT) of vocal responses, we measured the intensity, the fundamental frequency (f0) and the first and second formants of the vocalization. The RTs showed that the long and high-pitched vocal responses were associated with large numbers, while short and low-pitched vocal responses were associated with small numbers. It was also found that high-pitched vocalizations were mapped with the odd numbers, while the low-pitched vocalizations were mapped with the even numbers. Finally, large numbers increased the f0 values. The study shows systematic interactions between the processes that represent number magnitude and produce vocal responses.

Sharp and round shapes of seen objects have distinct influences on vowel and consonant articulation.

The shape and size-related sound symbolism phenomena assume that, for example, the vowel [i] and the consonant [t] are associated with sharp-shaped and small-sized objects, whereas [ɑ] and [m] are associated with round and large objects. It has been proposed that these phenomena are mostly based on the involvement of articulatory processes in representing shape and size properties of objects. For example, [i] might be associated with sharp and small objects, because it is produced by a specific front-close shape of articulators. Nevertheless, very little work has examined whether these object properties indeed have impact on speech sound vocalization. In the present study, the participants were presented with a sharp- or round-shaped object in a small or large size. They were required to pronounce one out of two meaningless speech units (e.g., [i] or [ɑ]) according to the size or shape of the object. We investigated how a task-irrelevant object property (e.g., the shape when responses are made according to size) influences reaction times, accuracy, intensity, fundamental frequency, and formant 1 and formant 2 of vocalizations. The size did not influence vocal responses but shape did. Specifically, the vowel [i] and consonant [t] were vocalized relatively rapidly when the object was sharp-shaped, whereas [u] and [m] were vocalized relatively rapidly when the object was round-shaped. The study supports the view that the shape-related sound symbolism phenomena might reflect mapping of the perceived shape with the corresponding articulatory gestures.

Hypoxia exposure and B-type natriuretic peptide release from Langendorff heart of rats.

AIM: We studied whether available oxygen without induced mechanical stretch regulates the release of the biologically active B-type natriuretic peptide (BNP) from Langendorff heart. METHODS: Rat hearts were isolated and perfused with a physiological Krebs-Henseleit solution at a constant hydrostatic pressure in Langendorff set-up. The basal O2 level of perfusate (24.4 ± 0.04 mg L-1 ) was gradually lowered to 3.0 ± 0.01 mg L-1 over 20 min using N2 gas (n = 7). BNP and O2 level were measured from coronary flow. During control perfusions (n = 5), the O2 concentration was kept at 26.6 ± 0.3 mg L-1 . RESULTS: A low oxygen concentration in the perfusate was associated with a significant increase in BNP release (F = 40.4, P < 0.001). Heart rate decreased when the oxygen concentration in the perfusate reached 9.1 ± 0.02 mg L-1 and continued to fall in lower oxygen concentrations (F = 14.8, P < 0.001). There was also a significant but inverse correlation between BNP and oxygen in the coronary flow (R2  = 0.27, P < 0.001). CONCLUSION: In the spontaneously beating Langendorff rat heart, a decreasing concentration of oxygen in the ingoing perfusion increased the secretion of BNP. The effect of oxygen was independent of mechanical stretch of the heart as it occurred even when the heart rate decreased but the pressure conditions remained constant. The difference in the oxygen capacitance of blood and Krebs-Henseleit solution appears to be a major factor affecting secretion of BNP, which is correlated with the oxygen tension of myocardial cells and affected both by the oxygen concentration and capacitance of solution perfusing the heart and by the coronary flow.

Double resonant absorption measurement of acetylene symmetric vibrational states probed with cavity ring down spectroscopy.

A novel mid-infrared/near-infrared double resonant absorption setup for studying infrared-inactive vibrational states is presented. A strong vibrational transition in the mid-infrared region is excited using an idler beam from a singly resonant continuous-wave optical parametric oscillator, to populate an intermediate vibrational state. High output power of the optical parametric oscillator and the strength of the mid-infrared transition result in efficient population transfer to the intermediate state, which allows measuring secondary transitions from this state with a high signal-to-noise ratio. A secondary, near-infrared transition from the intermediate state is probed using cavity ring-down spectroscopy, which provides high sensitivity in this wavelength region. Due to the narrow linewidths of the excitation sources, the rovibrational lines of the secondary transition are measured with sub-Doppler resolution. The setup is used to access a previously unreported symmetric vibrational state of acetylene, ν1+ν2+ν3+ν4 (1)+ν5 (-1) in the normal mode notation. Single-photon transitions to this state from the vibrational ground state are forbidden. Ten lines of the newly measured state are observed and fitted with the linear least-squares method to extract the band parameters. The vibrational term value was measured to be at 9775.0018(45) cm(-1), the rotational parameter B was 1.162 222(37) cm(-1), and the quartic centrifugal distortion parameter D was 3.998(62) × 10(-6) cm(-1), where the numbers in the parenthesis are one-standard errors in the least significant digits.

Mid-infrared optical parametric oscillators and frequency combs for molecular spectroscopy.

Nonlinear optical frequency conversion is one of the most versatile methods to generate wavelength-tunable laser light in the mid-infrared region. This spectral region is particularly important for trace gas detection and other applications of molecular spectroscopy, because it accommodates the fundamental vibrational bands of several interesting molecules. In this article, we review the progress of the most significant nonlinear optics instruments for widely tunable, high-resolution mid-infrared spectroscopy: continuous-wave optical parametric oscillators and difference frequency generators. We extend our discussion to mid-infrared optical frequency combs, which are becoming increasingly important spectroscopic tools, owing to their capability of highly sensitive and selective parallel detection of several molecular species. To illustrate the potential and limitations of mid-infrared sources based on nonlinear optics, we also review typical uses of these instruments in both applied and fundamental spectroscopy.

Radiocarbon dioxide detection based on cavity ring-down spectroscopy and a quantum cascade laser.

Monitoring of radiocarbon (C14) in carbon dioxide is demonstrated using mid-infrared spectroscopy and a quantum cascade laser. The measurement is based on cavity ring-down spectroscopy, and a high sensitivity is achieved with a simple setup. The instrument was tested using a standardized sample containing elevated levels of radiocarbon. Radiocarbon dioxide could be detected from samples with an isotopic ratio C14/C as low as 50 parts-per-trillion, corresponding to an activity of 5 kBq/m(3) in pure CO(2), or 2 Bq/m(3) in air after extraction of the CO(2) from an air sample. The instrument is simple, compact, and robust, making it the ideal tool for on-site measurements. It is aimed for monitoring radioactive gaseous emissions in a nuclear power environment, during the operation and decommissioning of nuclear power plants. Its high sensitivity also makes it the ideal tool for the detection of leaks in radioactive waste repositories.

Shared processing of planning articulatory gestures and grasping.

It has been proposed that articulatory gestures are shaped by tight integration in planning mouth and hand acts. This hypothesis is supported by recent behavioral evidence showing that response selection between the precision and power grip is systematically influenced by simultaneous articulation of a syllable. For example, precision grip responses are performed relatively fast when the syllable articulation employs the tongue tip (e.g., [te]), whereas power grip responses are performed relatively fast when the syllable articulation employs the tongue body (e.g., [ke]). However, this correspondence effect, and other similar effects that demonstrate the interplay between grasping and articulatory gestures, has been found when the grasping is performed during overt articulation. The present study demonstrates that merely reading the syllables silently (Experiment 1) or hearing them (Experiment 2) results in a similar correspondence effect. The results suggest that the correspondence effect is based on integration in planning articulatory gestures and grasping rather than requiring an overt articulation of the syllables. We propose that this effect reflects partially overlapped planning of goal shapes of the two distal effectors: a vocal tract shape for articulation and a hand shape for grasping. In addition, the paper shows a pitch-grip correspondence effect in which the precision grip is associated with a high-pitched vocalization of the auditory stimuli and the power grip is associated with a low-pitched vocalization. The underlying mechanisms of this phenomenon are discussed in relation to the articulation-grip correspondence.

Aspirin in the prevention of pre-eclampsia in high-risk women: a randomised placebo-controlled PREDO Trial and a meta-analysis of randomised trials.

OBJECTIVE: To study the effect of aspirin in the prevention of pre-eclampsia in high-risk women. DESIGN: Randomised, double-blinded, placebo-controlled trial. SETTING: Maternity clinics in ten Finnish hospitals participating in the PREDO Project. SAMPLE: A total of 152 women with risk factors for pre-eclampsia and abnormal uterine artery Doppler velocimetry. METHODS: Participants were randomised to start either aspirin 100 mg/day or placebo at 12 + 0 to 13 + 6 weeks + days of gestation. Because of the limited power of this trial, we also conducted a meta-analysis of randomised controlled trials that included data on 346 women with abnormal uterine artery Doppler flow velocimetry, and aspirin 50-150 mg/day started at or before 16( ) weeks of gestation. MAIN OUTCOME MEASURE: Pre-eclampsia, gestational hypertension and birthweight standard deviation (SD) score. Outcome measures for the meta-analysis were pre-eclampsia, severe pre-eclampsia, preterm (diagnosed <37 + 0 weeks of gestation) and term pre-eclampsia. RESULTS: From the 152 randomised women, 121 were included in the final analysis. Low-dose aspirin did not reduce the rate of pre-eclampsia (relative risk [RR] 0.7, 95% CI 0.3-1.7); gestational hypertension (RR 1.6, 95% CI 0.6-4.2); early-onset pre-eclampsia (diagnosed <34 + 0 weeks of gestation) (RR 0.2, 95% CI 0.03-2.1); or severe pre-eclampsia (RR 0.4, 95% CI 0.1-1.3); and the results were not statistically significant in an intention-to-treat analysis. However, our meta-analysis, including the current data, suggested that low-dose aspirin initiated before 16 weeks of gestation reduces the risk of pre-eclampsia (RR 0.6, 95% CI 0.4-0.8) and severe pre-eclampsia (RR 0.3, 95% CI 0.1-0.7). CONCLUSIONS: Our trial showed no statistically significant effect of aspirin in preventing pre-eclampsia in high-risk women. However, our meta-analysis suggested that aspirin may reduce the incidence of pre-eclampsia.

Selective tuning of cortical sound-feature processing by language experience.

In 'quantity-languages', such as Japanese or Finnish, sound duration is linguistically relevant. We showed that quantity-language speakers were superior to speakers of a non-quantity language in discriminating the duration of even non-speech sounds. In contrast, there was no group difference in the discrimination of sound frequency. This result, obtained both by behavioural and neural indices at attentive and automatic levels of processing, indicates precise feature-specific tuning of the auditory-cortex functions by the mother tongue.

Thyrotropin regulates adenosine A(1) receptor expression in rat thyroid FRTL-5 cells.

The effect of thyrotropin (TSH), on adenosine A(1) receptor expression in thyroid FRTL-5 cells was examined by [(3)H]-1, 3-dipropyl-,8-cyclopentyl xanthine ([(3)H]-DPCPX) binding on cells in suspension and on membrane preparation, and by in situ mRNA labelling. The estimated K(D) for intact cells was 0.19 nM and about 47,000 binding sites per cell were found in cells constantly grown in the presence of TSH. Three days deprivation of TSH decreased the number of [(3)H]-DPCPX binding sites without any significant effect of K(D). Reintroduction of TSH to the cells returned the higher level of A(1) receptors both in suspension binding studies on whole cells and on membrane preparations. In situ hybridization revealed that TSH evoked an increase in the number of cells densely labelled with a probe against A(1) receptor mRNA. The potency of the A(1) receptor agonist N(6)-cyclohexyladenosine (CHA) as an inhibitor of cyclic AMP formation induced by forskolin was increased in TSH-treated cells, with a shift in the IC(50) from 2.05 nM in TSH-deprived cells to 0.14 nM in TSH-treated cells. Since the activation of A(1) receptors inhibits TSH-mediated cyclic AMP signalling, our results suggest a regulatory feedback mechanism between signalling via adenosine A(1) receptors and TSH receptors.

The role of adenosine A(1) receptors in the ATP-evoked Ca(2+) response in rat thyroid FRTL-5 cells.

The effect of adenosine A(1) receptor activation on the ATP-induced increase in intracellular free Ca(2+) was studied in control and protein kinase C down-regulated Fisher rat thyroid (FRTL-5) cells. Long-term phorbol ester treatment, which leads to protein kinase C down-regulation, enhanced the ATP-evoked extracellular Ca(2+) influx. The increased Ca(2+) influx was antagonized by the adenosine A(1) receptor antagonist 8-cyclopentyl-1, 3-dipropylxanthine (DPCPX). [3H]DPCPX binding studies revealed that phorbol ester-treatment increased the number of adenosine A(1) receptors. The adenosine A(1) receptor-mediated inhibition of the cyclic AMP formation was not affected by the increased receptor number. We conclude that the enhanced ATP-evoked Ca(2+) influx in protein kinase C down-regulated cells is mediated by adenosine formed by hydrolysis of ATP, and that this adenosine interacts with the increased number of A(1) receptors. The mechanism by which adenosine enhances Ca(2+) entry is not known. Thus, the larger number of adenosine A(1) receptors broadens the spectrum of adenosine A(1) receptor affected signaling systems in FRTL-5 cells.

Extracellular ATP-mediated phospholipase A(2) activation in rat thyroid FRTL-5 cells: regulation by a G(i)/G(o) protein, Ca(2+), and mitogen-activated protein kinase.

We investigated the mechanism of phospholipase A(2) (PLA(2)) activation in response to the P2 receptor agonist ATP in rat thyroid FRTL-5 cells. The PLA(2) activity was determined by measuring the release of [(3)H]-arachidonic acid (AA) from prelabeled cells. ATP evoked a dose- and time-dependent AA release. This release was totally inhibited by pertussis toxin (PTX) treatment, indicating the involvement of a G(i)/G(o) protein. The AA release was also diminished by chelating extracellular Ca(2+) with EGTA or by inhibiting influx of Ca(2+) using Ni(2+). Although the activation of protein kinase C (PKC) by 12-phorbol 13-myristate acetate (PMA) alone did not induce any AA release, the ATP-evoked AA release was significantly reduced when PKC was inhibited by GF109203X or by a long incubation with PMA to downregulate PKC. Both the ATP-evoked AA release and the mitogen-activated protein kinase (MAP kinase) phosphorylation were decreased by the MAP kinase kinase (MEK) inhibitor PD98059. Furthermore, the ATP-evoked MAP kinase phosphorylation was also inhibited by GF109203X and by downregulation of PKC, suggesting a PKC-mediated activation of MAP kinase. Inhibiting Src-like kinases by PP1 attenuated both the MAP kinase phosphorylation and the AA release. These results suggest that these kinases are involved in the regulation of MAP kinase and PLA(2) activation. Elevation of intracellular cAMP by TSH or by dBucAMP did not induce a phosphorylation of MAP kinase. Furthermore, neither the ATP-evoked AA release nor the MAP kinase phosphorylation were attenuated by TSH or dBucAMP. Taken together, our results suggest that ATP regulates the activation of PLA(2) by a G(i)/G(o) protein-dependent mechanism. Moreover, Ca(2+), PKC, MAP kinase, and Src-like kinases are also involved in this regulatory process.

Sphingosylphosphorylcholine activates Gq, Gi-2, and Gi-3 in thyroid FRTL-5 cells: implications for the activation of calcium fluxes and Na+-H+ exchange.

In the present investigation of rat thyroid FRTL-5 cells, we show using reverse-transcriptase PCR that these cells express both Edg-1 and Edg-5. We show using a [35S]GTPgammaS-binding assay that sphingosylphosphorylcholine (SPC), which binds to both Edg-1 and EDG-5, activates Gq, Gi-2, and Gi-3 proteins. SPC potently increases intracellular free calcium concentrations ([Ca2+]i). This effect is mediated through both Gq and Gi proteins, as the mobilization of sequestered calcium was insensitive to pertussis toxin (i.e., mediated by Gq), while the SPC-evoked calcium entry was inhibited by pretreatment with pertussis toxin (i.e., mediated by Gi). Furthermore, SPC in a concentration-dependent manner increases intracellular pH in acidified cells via a Na+-H+ exchange mechanism. The enhanced activation of Na+-H+ exchange is independent of both an increase in [Ca2+]i and an activation of protein kinase C. The effect of SPC on Na+-H+ exchange is insensitive to pertussis toxin, suggesting an effect mediated via Gq.

In the dose range of 0.5-2.0 mg/kg, acetylsalicylic acid does not affect prostacyclin production in hypertensive pregnancies.

OBJECTIVE: To determine the dose of acetylsalicylic acid (ASA), that inhibits the production of the vasoconstrictive, aggregatory thromboxane A2 while sparing the production of the vasodilatory antiaggregatory prostacyclin. DESIGN: A controlled study comparing the effects of three doses of ASA on the production of thromboxane A2 and prostacyclin. METHODS: Seven pregnant hypertensive patients and five non-pregnant healthy women received 0.5, 1.0 and 2.0 mg/kg/day of ASA, each dose for 10-12 days, the treatment periods following each other immediately. Seven normotensive pregnant women served as controls and were given no ASA. Blood and urine samples were taken at baseline and after the treatment periods to determine serum thromboxane B2 and the urinary 2.3-dinor-6-ketoprostaglandin F1alpha and 11-dehydrothromboxaneB2, the major stable metabolites of prostacyclin and thromboxane A2, respectively. RESULTS: The urinary excretion of 11-dehydrothromboxaneB2 was significantly higher in both hypertensive (34.9+/-18.3 pg/micromol creatinine) and normotensive (39.3+/-14.4 pg/micromol creatinine) pregnant women than in non-pregnant women (14.8+/-6.4 pg/micromol creatinine). The urinary excretion of 2.3-dinor-6-ketoprostaglandinF1alpha was also higher in normotensive pregnant women (93.9+/-50.9 pg/micromol creatinine) than in non-pregnant women (18.2+/-11.3 pg/micromol creatinine). The excretion rate of 2.3-dinor-6-ketoprostaglandinF1alpha in hypertensive patients was lower than in normotensive pregnant women (44.7+/-24.2 pg/micromol creatinine). At baseline the urinary 2.3-dinor-6-ketoprostaglandin F1alpha/11-dehydrothromboxaneB2 ratio was almost the same in the hypertensive patients (1.6) and in the non-pregnant women (1.2). The ratio was 2.6 in normotensive pregnant women. In the hypertensive group, already the lowest dose of ASA inhibited urinary 11-dehydrothromboxaneB2 excretion significantly. Because none of the doses of ASA inhibited 2.3-dinor-6-ketoprostaglandinF1alpha production, the 2.3-dinor-6-ketoprostaglandinF1alpha/11-dehydrothromboxaneB2 ratio was shifted in the favor of prostacyclin at all dose levels. In the non-pregnant women, even the highest dose level of ASA failed to affect the ratio. CONCLUSION: In the dose range of 0.5-2.0 mg/kg/day, ASA has a favorable effect on the ratio of prostacyclin to thromboxane A2 in hypertensive pregnancies.

Pre-attentive detection of vowel contrasts utilizes both phonetic and auditory memory representations.

Event-related brain potentials (ERP) were recorded to infrequent changes of a synthesized vowel (standard) to another vowel (deviant) in speakers of Hungarian and Finnish language, which are remotely related to each other with rather similar vowel systems. Both language groups were presented with identical stimuli. One standard-deviant pair represented an across-vowel category contrast in Hungarian, but a within-category contrast in Finnish, with the other pair having the reversed role in the two languages. Both within- and across-category contrasts elicited the mismatch negativity (MMN) ERP component in the native speakers of either language. The MMN amplitude was larger in across- than within-category contrasts in both language groups. These results suggest that the pre-attentive change-detection process generating the MMN utilized both auditory (sensory) and phonetic (categorical) representations of the test vowels.

Sphingosine 1-phosphate mobilizes sequestered calcium, activates calcium entry, and stimulates deoxyribonucleic acid synthesis in thyroid FRTL-5 cells.

Sphingosine 1-phosphate (SPP) potently mobilizes sequestered calcium and is a mitogen in several cell types. In the present investigation, we have evaluated the effect of SPP on intracellular free calcium concentration ([Ca2+]i) and synthesis of DNA in thyroid FRTL-5 cells. SPP rapidly and transiently mobilized sequestered calcium and stimulated entry of extracellular calcium. The entry of calcium, but not the mobilization, was in part inhibited by pretreatment with pertussis toxin (Ptx), and by activation of protein kinase C. SPP did not stimulate the production of inositol 1,4,5-trisphosphate. SPP stimulated the incorporation of 3H-thymidine in a time- and dose-dependent manner. The effect was not inhibited by Ptx. Furthermore, SPP stimulated the activation of the proto-oncogene c-fos. SPP rapidly tyrosine-phosphorylated an approximately 66 kDa protein. This phosphorylation persisted for at least 1 h. Pretreatment of the cells with genistein abolished the SPP-evoked tyrosine phosphorylation, and attenuated the SPP-evoked increase in [Ca2+]i. Furthermore, the SPP-evoked activation of Na+-H+ exchange was inhibited by genistein. The phosphorylation was not attenuated by pretreatment of the cells with Ptx. SPP per se did not affect cellular cAMP levels but attenuated the TSH-evoked increase in cAMP. As the effect of SPP might be due to activation of phospholipase D, we tested whether phosphatidic acid (PA) mobilized calcium or stimulated the incorporation of 3H-thymidine. PA mobilized sequestered calcium but did not stimulate calcium entry. PA very modestly enhanced the incorporation of 3H-thymidine. Our results suggest, that SPP stimulates DNA synthesis and activates entry of calcium in FRTL-5 cells. The effect on calcium entry appears to be dependent, at least in part, on one or several tyrosine kinases.

Adenosine inhibits DNA synthesis stimulated with TSH, insulin, and phorbol 12-myristate 13-acetate in rat thyroid FRTL-5 cells.

Adenosine has been shown to modulate cell proliferation in FRTL-5 thyroid cells, although the mechanisms by which this interaction occurs is still unclear. In the present study we investigated the effects of adenosine on the 3H-thymidine incorporation, cell cycle kinetics, and expression of the transcription factor c-Fos in cells stimulated via three different mitogenic pathways, i.e., by thyroid stimulating hormone (TSH) [adenosine 3',5'-cyclic monophosphate(cAMP)], insulin (tyrosine kinase), or phorbol 12-myristate 13-acetate (protein kinase C). Addition of adenosine to cells grown in medium containing hormones and serum did not inhibit the incorporation of 3H-thymidine. If adenosine was added to hormone-deprived cells together with any of the tested mitogens, the stimulation of the 3H-thymidine incorporation was inhibited in a dose-dependent manner. The inhibition was significantly lower when the cells were preincubated with TSH or insulin for 48 h. Flow cytometric studies showed that adenosine evoked an inhibition of the cells in the G0/G1 phase. Submaximal doses of adenosine (10 nM-10 microM) were able to induce c-Fos expression in FRTL-5 cells. However, the mitogen-induced expression of c-Fos was not reduced by maximal dose of adenosine (100 microM). The effect of adenosine on DNA synthesis was not dependent on pertussis toxin-sensitive G-proteins. In addition, adenosine A1- or A2- receptor antagonists did not block the effect of adenosine. The effect of adenosine was abolished by treatment of the cells with adenosine deaminase, suggesting that the observed effect was not mediated by a metabolite of adenosine. The results suggest that adenosine is an effective blocker of mitogen-evoked DNA synthesis of FRTL-5 cells, provided that adenosine is administered simultaneously with the mitogen.