Identifying Post-Acute Sequelae of SARS-CoV-2 Among Children in New York State Medicaid Managed Care.

Persons who contract COVID-19 are at risk of developing post-acute sequelae of SARS-CoV-2 (PASC). The objective of this study was to describe the incidence of PASC in a pediatric Medicaid population. Using a retrospective cohort of children enrolled in New York State Medicaid Managed Care we compared incident diagnoses between children with a positive laboratory test for SARS-CoV-2 in 2021 to children without a positive test in 2021 and children with a viral respiratory diagnosis in 2019. Logistic regression models estimated adjusted odds ratios using the Cohen's d statistic to assess the strength of associations. Most unadjusted incidence of clinical outcomes were less than 1% for all cohorts. Relative to the 2021 comparison cohort, significant increases among SARS-CoV-2 cases were observed in sequela of infectious disease conditions, general signs and symptoms, and pericarditis and pericardial disease and for the 2019 comparison, sequela of infectious disease conditions and suicidal ideation. However, associations were mostly determined to be weak or marginal. In this low socioeconomic status pediatric population, incidence of new clinical sequelae was low with mostly weak or marginal increases associated with SARS-CoV-2 infection. Though the incidence was low, some outcomes may be severe. Observed associations may have been impacted by pandemic behavior modification including social distancing policies.

Pedagogy, Partnership, and Collaboration: A Longitudinal, Empirical Study of Serious Educational Gameplay in Secondary Biology Classrooms.

The use of serious educational games has the potential to increase student learning outcomes in science education by providing students with opportunities to explore phenomena in ways that vary from traditional instruction; yet, empirical research to support this assertion is limited. This study aimed to explore deeply what learning gains were associated with the use of three serious educational games (SEGs) created for use in secondary biology classrooms that partner teachers implemented during a 2-week curriculum unit. This longitudinal, mixed method study includes a control year, in which we examined how six highly qualified teachers taught students (n = 407) a 2-week curriculum unit addressing cellular biology without the SEGs, followed by 2 years in which the teachers integrated the SEGs into the curriculum unit with students (n =871). Data were collected from multiple sources, including a validated content pre- and post-test measure, embedded gameplay data, participant observation, teacher interviews, and focus groups. Quantitative findings showed significant learning gains associated with students who experienced the game condition during year 2, when compared with the control condition. During the replication year (year 3), learning gains increased again, compared with year two. Although the SEGs did not change between years 2 and 3, teachers were provided real-time access to students' performance during gameplay. Thematic analysis of observation notes, teacher interviews, and student performance in-game identified four affordances teachers identified related to the use of serious educational games in their classrooms and the extended partnership model employed. Implications for researchers and game designers are discussed.

Kinome Analysis of Honeybee (Apis mellifera L.) Dark-Eyed Pupae Identifies Biomarkers and Mechanisms of Tolerance to Varroa Mite Infestation.

The mite Varroa destructor is a serious threat to honeybee populations. Selective breeding for Varroa mite tolerance could be accelerated by biomarkers within individual bees that could be applied to evaluate a colony phenotype. Previously, we demonstrated differences in kinase-mediated signaling between bees from colonies of extreme phenotypes of mite susceptibility. We expand these findings by defining a panel of 19 phosphorylation events that differ significantly between individual pupae from multiple colonies with distinct Varroa mite tolerant phenotypes. The predictive capacity of these biomarkers was evaluated by analyzing uninfested pupae from eight colonies representing a spectrum of mite tolerance. The pool of biomarkers effectively discriminated individual pupae on the basis of colony susceptibility to mite infestation. Kinome analysis of uninfested pupae from mite tolerant colonies highlighted an increased innate immune response capacity. The implication that differences in innate immunity contribute to mite susceptibility is supported by the observation that induction of innate immune signaling responses to infestation is compromised in pupae of the susceptible colonies. Collectively, biomarkers within individual pupae that are predictive of the susceptibility of colonies to mite infestation could provide a molecular tool for selective breeding of tolerant colonies.

HIV infection is an independent risk factor for decreased 6-minute walk test distance.

BACKGROUND: Ambulatory function predicts morbidity and mortality and may be influenced by cardiopulmonary dysfunction. Persons living with HIV (PLWH) suffer from a high prevalence of cardiac and pulmonary comorbidities that may contribute to higher risk of ambulatory dysfunction as measured by 6-minute walk test distance (6-MWD). We investigated the effect of HIV on 6-MWD. METHODS: PLWH and HIV-uninfected individuals were enrolled from 2 clinical centers and completed a 6-MWD, spirometry, diffusing capacity for carbon monoxide (DLCO) and St. George's Respiratory Questionnaire (SGRQ). Results of 6-MWD were compared between PLWH and uninfected individuals after adjusting for confounders. Multivariable linear regression analysis was used to determine predictors of 6-MWD. RESULTS: Mean 6-MWD in PLWH was 431 meters versus 462 in 130 HIV-uninfected individuals (p = 0.0001). Older age, lower forced expiratory volume (FEV1)% or lower forced vital capacity (FVC)%, and smoking were significant predictors of decreased 6-MWD in PLWH, but not HIV-uninfected individuals. Lower DLCO% and higher SGRQ were associated with lower 6-MWD in both groups. In a combined model, HIV status remained an independent predictor of decreased 6-MWD (Mean difference = -19.9 meters, p = 0.005). CONCLUSIONS: HIV infection was associated with decreased ambulatory function. Airflow limitation and impaired diffusion capacity can partially explain this effect. Subjective assessments of respiratory symptoms may identify individuals at risk for impaired physical function who may benefit from early intervention.

Vasoplegic Shock Treated with Methylene Blue Complicated by Severe Serotonin Syndrome.

INTRODUCTION: Management of severe vasoplegic shock in overdose can be very challenging. We describe a case of severe refractory vasodilatory shock in poisoning where methylene blue (MB) was used with success. However, the patient subsequently developed severe Serotonin Syndrome (SS) as a result of an interaction between serotonergic drugs and MB. CASE REPORT: A 15-year-old male developed severe vasoplegic shock 1.5 hours after overdosing on several different medications including quetiapine slow release, quetiapine immediate release, desvenlafaxine slow release, venlafaxine, amlodipine, ramipril, fluoxetine, promethazine and lithium. His vasoplegic shock was resistant to high doses of noradrenaline and vasopressin. MB was administered 6.5 hours post ingestion and within 1 hour there was an improvement in his hemodynamic status and reduction of catecholamine requirements. Twelve hours post ingestion, he developed severe Serotonin Syndrome that lasted 5 days as a result of interaction between MB, a reversible monoamine oxidase inhibitor (MAO-I), and the antidepressants taken in overdose. MB had a calculated half-life of 38 hours. CONCLUSION: MB is a useful additional strategy for severe drug induced vasodilatory shock and may be potentially life-saving. Clinicians should be aware that it can interact with other drugs and cause life-threatening Serotonin Syndrome. Lower doses or shorter durations may be wise in patients at risk of this interaction.

Pramipexole Overdose Associated with Visual Hallucinations, Agitation and Myoclonus.

INTRODUCTION: Pramipexole is a dopamine D2 receptor agonist used to treat idiopathic Parkinson's disease and primary restless legs syndrome. There is limited information on pramipexole overdose. CASE REPORT: A 59-year-old male ingested 3 mg pramipexole, 2250 mg venlafaxine, 360 mg mirtazapine, with suicidal intent. He presented alert, had normal vital observations and normal pupillary reflexes. He was mildly agitated, reported visual hallucinations and was given 5 mg diazepam. He had a mildly elevated lactate of 1.7 mmol/L, but otherwise normal laboratory investigations. Overnight, he remained agitated with visual hallucinations and developed myoclonus while awake. He had increasing difficulty passing urine on a background of mild chronic urinary retention. On review, 14 h post-ingestion, he was hypervigilant, jittery and mildly agitated. He had pressured speech and difficulty focusing on questioning. He had a heart rate of 110 bpm, but had an otherwise normal examination, with no clonus or extrapyramidal effects. He was unable to mobilize due to dizziness and ataxia. Over the next few hours, he improved, the visual hallucinations and agitation resolved and he mobilized independently. Pramipexole was measured with liquid chromatography mass spectrometry. The initial plasma pramipexole concentration was 34.2 ng/mL (therapeutic range 0.2 to 7 ng/mL), 9 h post-overdose. Concentration time data fitted a one-compartment model with an estimated elimination half-life of 18 h. DISCUSSION: Pramipexole overdose with hallucination, agitation, and myoclonus is consistent with adverse effects reported with therapeutic toxicity, but mirtazapine and venlafaxine may have contributed. Pramipexole concentrations exceeded the therapeutic range for over 24 h. With the increasing use of pramipexole in restless legs syndrome, adult overdoses may become more common.

Using Virtual Pets to Promote Physical Activity in Children: An Application of the Youth Physical Activity Promotion Model.

A virtual pet was developed based on the framework of the youth physical activity promotion model and tested as a vehicle for promoting physical activity in children. Children in the treatment group interacted with the virtual pet for three days, setting physical activity goals and teaching tricks to the virtual pet when their goals were met. The virtual pet became more fit and learned more sophisticated tricks as the children achieved activity goals. Children in the control group interacted with a computer system presenting equivalent features but without the virtual pet. Physical activity and goal attainment were evaluated using activity monitors. Results indicated that children in the treatment group engaged in 1.09 more hours of daily physical activity (156% more) than did those in the control group. Physical activity self-efficacy and beliefs served as mediators driving this increase in activity. Children that interacted with the virtual pet also expressed higher intentions than children in the control group to continue physical activity in the future. Theoretical and practical potentials of using a virtual pet to systematically promote physical activity in children are discussed.

Occipital Artery Function during the Development of 2-Kidney, 1-Clip Hypertension in Rats.

This study compared the contractile responses elicited by angiotensin II (AII), arginine vasopressin (AVP), and 5-hydroxytryptamine (5-HT) in isolated occipital arteries (OAs) from sham-operated (SHAM) and 2-kidney, 1-clip (2K-1C) hypertensive rats. OAs were isolated and bisected into proximal segments (closer to the common carotid artery) and distal segments (closer to the nodose ganglion) and mounted separately on myographs. On day 9, 2K-1C rats had higher mean arterial blood pressures, heart rates, and plasma renin concentrations than SHAM rats. The contractile responses to AII were markedly diminished in both proximal and distal segments of OAs from 2K-1C rats as compared to those from SHAM rats. The responses elicited by AVP were substantially greater in distal than in proximal segments of OAs from SHAM rats and that AVP elicited similar responses in OA segments from 2K-1C rats. The responses elicited by 5-HT were similar in proximal and distal segments from SHAM and 2K-1C rats. These results demonstrate that continued exposure to circulating AII and AVP in 2K-1C rats reduces the contractile efficacy of AII but not AVP or 5-HT. The diminished responsiveness to AII may alter the physiological status of OAs in vivo.

Vasopressin-induced constriction of the isolated rat occipital artery is segment dependent.

BACKGROUND: Circulating factors delivered to the nodose ganglion (NG) by the occipital artery (OA) have been shown to affect vagal afferent activity, and thus the contractile state of the OA may influence blood flow to the NG. METHODS: OA were isolated and bisected into proximal and distal segments relative to the external carotid artery. RESULTS: Bisection highlighted stark differences between maximal contractile responses and OA sensitivity. Specifically, maximum responses to vasopressin and the V1 receptor agonist were significantly higher in distal than proximal segments. Distal segments were significantly more sensitive to 5-hydroxytryptamine (5-HT) and the 5-HT2 receptor agonist than proximal segments. Angiotensin II (AT)2, V2 and 5-HT(1B/1D) receptor agonists did not elicit vascular responses. Additionally, AT1 receptor agonists elicited mild, yet not significantly different maximal responses between segments. CONCLUSION: The results of this study are consistent with contractile properties of rat OA being mediated via AT1, V1 and 5-HT2 receptors and dependent upon the OA segment. Furthermore, vasopressin-induced constriction of the OA, regardless of a bolus dose or a first and second concentration-response curve, retained this unique segmental difference. We hypothesize that these segmental differences may be important in the regulation of blood flow through the OA in health and disease.

A novel vascular clip design for the reliable induction of 2-kidney, 1-clip hypertension in the rat.

The 2-kidney, 1-clip (2K1C) model has provided many insights into the pathogenesis of renovascular hypertension. However, studies using the 2K1C model often report low success rates of hypertension, with typical success rates of just 40-60%. We hypothesized that these low success rates are due to fundamental design flaws in the clips traditionally used in 2K1C models. Specifically, the gap widths of traditional silver clips may not be maintained during investigator handling and these clips may also be easily dislodged from the renal artery following placement. Therefore, we designed and tested a novel vascular clip possessing design features to maintain both gap width and position around the renal artery. In this initial study, application of these new clips to the left renal artery produced reliable and consistent levels of hypertension in rats. Nine-day application of clips with gap widths of 0.27, 0.25, and 0.23 mm elicited higher mean arterial blood pressures of 112 ± 4, 121 ± 6, and 135 ± 7 mmHg, respectively (n = 8 for each group), than those of sham-operated controls (95 ± 2 mmHg, n = 8). Moreover, 8 out of 8 rats in each of the 0.23 and 0.25 mm 2K1C groups were hypertensive, whereas 7 out of 8 rats in the 0.27 mm 2K1C group were hypertensive. Plasma renin concentrations were also increased in all 2K1C groups compared with sham-operated controls. In summary, this novel clip design may help eliminate the large degree of unreliability commonly encountered with the 2K1C model.

Multiphoton microscopy and fluorescence lifetime imaging provide a novel method in studying drug distribution and metabolism in the rat liver in vivo.

Multiphoton microscopy has been shown to be a useful tool in studying drug distribution in biological tissues. In addition, fluorescence lifetime imaging provides information about the structure and dynamics of fluorophores based on their fluorescence lifetimes. Fluorescein, a commonly used fluorescent probe, is metabolized within liver cells to fluorescein mono-glucuronide, which is also fluorescent. Fluorescein and its glucuronide have similar excitation and emission spectra, but different fluorescence lifetimes. In this study, we employed multiphoton fluorescence lifetime imaging to study the distribution and metabolism of fluorescein and its metabolite in vivo in rat liver. Fluorescence lifetime values in vitro were used to interpret in vivo data. Our results show that the mean fluorescence lifetimes of fluorescein and its metabolite decrease over time after injection of fluorescein in three different regions of the liver. In conclusion, we have demonstrated a novel method to study a fluorescent compound and metabolite in vivo using multiphoton fluorescence lifetime imaging.

Evaluation of the possible role of prostaglandin F(2 alpha) in laminitis induced in horses by nasogastric administration of black walnut heartwood extract.

OBJECTIVE: To provide insights into the role of prostaglandin F(2 alpha) (PGF(2 alpha)) in the developmental stages of laminitis induced in horses by ingestion of black walnut heartwood extract (BWHE). SAMPLE POPULATION: 10 adult mixed-breed horses. PROCEDURES: Horses were separated into 2 groups and were euthanatized at 12 hours after placebo (water) administration (control horses) or after BWHE administration and development of Obel grade 1 laminitis. Blood samples were obtained to determine plasma PGF(2 alpha) concentrations hourly for the first 4 hours and subsequently every 2 hours after substance administration. Laminar arteries and veins were isolated, and responses to increasing concentrations of PGF(2 alpha) were measured before and after preincubation of blood vessels with prostanoid and thromboxane receptor antagonists SQ 29,548, SC-19220, and AH 6809. RESULTS: Plasma PGF(2 alpha) concentrations increased in horses given BWHE; the WBC count decreased concurrently. In control horses, PGF(2 alpha) was a potent contractile agonist for laminar veins but not for laminar arteries. In horses given BWHE, PGF(2 alpha) was similarly selective for laminar veins; however, the magnitude of PGF(2 alpha)-induced venoconstriction was less than that in control horses. After preincubation with SQ 29,548, laminar veins from control horses responded to PGF(2 alpha) with a small degree of dilation, whereas laminar veins from horses given BWHE did not. CONCLUSIONS AND CLINICAL RELEVANCE: PGF(2 alpha) may play a role in the inflammatory and vascular dysfunction associated with the prodromal stages of laminitis. Prostanoids such as PGF(2 alpha) may be viable targets for the prevention of acute laminitis in horses.

Thromboxane and isoprostanes as inflammatory and vasoactive mediators in black walnut heartwood extract induced equine laminitis.

Inflammation and vascular dysfunction occur concurrently during the prodromal stages of equine laminitis. The aim of this study was to provide insights into the role that thromboxane and isoprostanes may play in the development of black walnut heartwood extract (BWHE)-induced laminitis. Horses were divided into two groups, either control or BWHE-administered horses. Plasma concentrations of thromboxane increased transiently after administration of BWHE and coincided with the nadir in white blood cell counts, whereas plasma concentrations of iso-prostaglandin PGF(2alpha) (iso-PGF(2alpha)) did not change in either group. At 12h (for the control group) or Obel grade 1 laminitis (for the BWHE group) the horses were euthanized and laminar tissue collected. Laminar arteries and veins were used in functional studies with vasoconstrictor substances and tissue samples were used for the determination of laminar iso-PGF(2alpha) concentrations. Laminar tissue concentrations of iso-PGF(2alpha) were significantly greater in BWHE horses when compared to control horses. In parallel studies concentrations of iso-PGF(2alpha) in laminar tissue samples obtained 1.5 and 3h after administration of BWHE were indistinguishable from those for control horses at 3 or 12h after administration of an equal volume of water. Laminar vessel constrictor responses to either a thromboxane mimetic (U46619), iso-prostaglandin PGE(2) (iso-PGE(2)) or iso-PGF(2alpha) were determined using small vessel myographs. In some vessels, the effects of putative prostanoid and thromboxane receptor antagonists, SQ 29,548, SC-19220 and AH 6809, upon contractile responses were determined. In control horses, U46619, iso-PGF(2alpha) and iso-PGE(2) more potently and efficaciously constricted laminar veins when compared to laminar arteries. Responses of laminar veins from BWHE horses to iso-PGE(2) were similar to those of laminar veins from control horses, whereas iso-PGF(2alpha) elicited significantly greater responses in laminar veins from BWHE horses when compared to controls. In contrast, responses to U46619 were smaller in laminar veins isolated from BWHE horses when compared to those in laminar veins from control horses. In the presence of SQ 29,548, iso-PGF(2alpha) elicited a small dilation in laminar veins from control horses, which was not apparent in laminar veins from BWHE horses. These results are consistent with both systemic and local inflammatory events occurring during the prodromal stages of BWHE-induced laminitis. Because laminar veins are sensitive to thromboxane and isoprostanes, these substances may act as conduits between the inflammatory and vascular events occurring in laminitis and may be therapeutic targets for this crippling condition.

Equine laminitis: a journey to the dark side of venous.

Equine laminitis is a crippling condition that continues to defy repeated efforts to delineate the precise mechanisms involved and develop effective therapeutic strategies for use in the clinic. In this article, the possible role of dysfunction of the laminar vasculature is discussed, with particular emphasis on the venous side of the laminar microvasculature and the possible role(s) that metabolic syndrome and thrombosis may play in the dysfunction observed in the laminar microvasculature during the development of laminitis.

AMP-activated protein kinase and hypoxic pulmonary vasoconstriction.

Hypoxic pulmonary vasoconstriction is a vital homeostatic mechanism that aids ventilation-perfusion matching in the lung, for which the underlying mechanism(s) remains controversial. However, our most recent investigations strongly suggest that hypoxic pulmonary vasoconstriction is precipitated, at least in part, by the inhibition of mitochondrial oxidative phosphorylation by hypoxia, an increase in the AMP/ATP ratio and consequent activation of AMP-activated protein kinase (AMPK). Unfortunately, these studies lacked the definitive proof that can only be provided by selectively blocking AMPK-dependent signalling cascades. The aim of the present study was, therefore, to determine the effects of the AMPK inhibitor compound C upon: (1) phosphorylation in response to hypoxia of a classical AMPK substrate, acetyl CoA carboxylase, in rat pulmonary arterial smooth muscle and (2) hypoxic pulmonary vasoconstriction in rat isolated intrapulmonary arteries. Acetyl CoA carboxylase phosphorylation was increased approximately 3 fold in the presence of hypoxia (pO(2) = 16-21 mm Hg, 1 h) and 5-aminoimidazole-4-carboxamide riboside (AICAR; 1 mM; 4 h) and in a manner that was significantly attenuated by the AMPK antagonist compound C (40 microM). Most importantly, pre-incubation of intrapulmonary arteries with compound C (40 microM) inhibited phase II, but not phase I, of hypoxic pulmonary vasoconstriction. Likewise, compound C (40 microM) inhibited constriction by AICAR (1 mM). The results of the present study are consistent with the activation of AMPK being a key event in the initiation of the contractile response of pulmonary arteries to acute hypoxia.

Dietary structured lipids and phytosteryl esters: blood lipids and cardiovascular status in spontaneously hypertensive rats.

This study examined the dietary effects of enzymatically modified sesame oil with caprylic acid (structured lipids, SL) and phytosteryl esters (PE) on blood lipid profiles and cardiovascular parameters of spontaneously hypertensive rats (SHR) fed high-fat and high-cholesterol (HFHC) diets. The dietary groups were: normal diet (control), sesame oil (SO), SL, SO fortified with PE (SOP), and SL fortified with PE (SLP). After 9 weeks of feeding, the body weights, liver weights, and liver weight/body weight ratios in all HFHC-fed groups were higher than controls. Plasma total and LDL cholesterol levels in all HFHC-fed groups were similar to one another but higher than those in controls. Plasma HDL cholesterol levels in rats fed SOP and SLP were higher than those in controls or rats fed SO and SL. Plasma HDL/total cholesterol ratios in rats fed SOP and SLP were similar to those in controls and were higher than those in rats fed SO and SL. There was no difference in plasma lipid profiles between rats fed SO and SL. Arterial blood pressures (BP) in conscious HFHC-fed rats were similar to those in controls whereas heart rates (HR) in all HFHC-fed groups were similar to one another but were higher than that in controls. These findings demonstrate that (1) the dietary effects of SL on plasma lipid profiles and resting BP and HR are similar to those of SO, (2) PE had positive effects on plasma lipid profiles, and (3) 9-week intake of SL and PE did not have pronounced effects on resting BP but induced tachycardia in SHR.

Hemodynamic responses elicited by systemic injections of flavin adenine dinucleotide in anesthetized rats.

Flavin adenine dinucleotide (FAD) elicits an endothelium-dependent vasodilation in isolated rat mesenteric beds via activation of P2Y-purinoceptors. The aims of this study were to characterize the hemodynamic responses elicited by systemic injections of FAD and flavin mononucleotide (FMN) in anesthetized rats and to determine the role of nitric oxide synthase (NOS), cyclooxygenase, P2Y/P2X-purinoceptors, and muscarinic receptor in these responses. FAD (0.05-1.0 micromol/kg, iv) elicited dose-dependent decreases in heart rate (HR), mean arterial blood pressure (MAP), and hindquarter vascular resistance (HQR), whereas it elicited an initial increase and then a decrease in mesenteric (MR) vascular resistance. The FAD-induced responses were not affected by the P2Y/P2X-purinoceptor antagonist suramin, the muscarinic receptor antagonist methyl-atropine, or the cyclooxygenase inhibitor indomethacin. The vasodilator actions of FAD were unaffected by the NOS inhibitor N-nitro-L-arginine methyl ester (L-NAME), whereas the bradycardia elicited by higher doses of FAD were diminished by L-NAME. FMN did not elicit hemodynamic responses in the absence or presence of L-NAME. In summary, FAD-induced bradycardia depends, in part, on the activation of NOS, whereas the vasodilator actions of FAD are not obviously due to newly synthesized nitrosyl factors. These findings and those in our companion manuscript support the concepts that the adenine moiety confers biological activity to FAD, which releases preformed pools of nitrosyl factors.

Effects of Rho-kinase and Src protein tyrosine kinase inhibition on agonist-induced vasoconstriction of arteries and veins of the equine laminar dermis.

OBJECTIVE: To determine the effects of inhibition of Rho-kinase or Src-family protein tyrosine kinases (srcPTK) on agonist-induced contractile responses in equine laminar arteries and veins. SAMPLE POPULATION: Laminar arteries and veins obtained from 13 adult mixed-breed horses. PROCEDURES: Laminar vessels were mounted on myographs and exposed to phenylephrine (PE), 5-hydroxytryptamine (5-HT), prostaglandin F(2) (PGF(2)), and endothelin-1 (ET-1) with or without the Rho-kinase inhibitor Y-27632 (10 microM), srcPTK inhibitor PP2 (10 microM), or a negative control analogue for PP2 (PP3; 10 microM). RESULTS: Responses to PE were reduced by use of Y-27632 in laminar vessels (approx inhibition, 55%). However, Y-27632 reduced responses to 5-HT to a greater degree in veins than in arteries (approx inhibition of 55% and 35%, respectively). The Y-27632 also reduced responses of laminar veins to ET-1 by approximately 40% but had no effect on maximum responses of laminar arteries to ET-1, although a rightward shift in the concentration response curve was evident. Addition of PP2 reduced responses to PE, 5-HT, and PGF(2) in laminar veins by approximately 40%, 60%, and 65%, respectively, compared with responses after the addition of PP3; PP2 had no effect on responses to ET-1. In laminar arteries, PP2 reduced 5-HT-induced contractions by approximately 50% but did not affect responses to PE or ET-1. CONCLUSIONS AND CLINICAL RELEVANCE: Results of the study were consistent with activation of Rho-kinase being important during agonist-induced constriction in laminar vessels, activation of srcPTK being an agonist-dependent event, and more prominent roles for Rhokinase and srcPTK in veins than in arteries.

Flavin adenine dinucleotide may release preformed stores of nitrosyl factors from the vascular endothelium of conscious rats.

This study determined whether flavin adenine dinucleotide (FAD) may elicit vasodilation in conscious rats via release of preformed endothelium-derived nitrosyl factors. Injections 1-6 (inj(1-6)) of FAD (2.5 micromol/kg, IV) elicited pronounced and equivalent vasodilator responses in saline-treated rats. Inj(1) of FAD elicited pronounced vasodilation in L-NAME-treated rats pretreated with the nitric oxide (NO) synthesis inhibitor, NG-nitro-L-arginine (L-NAME; 50 micromol/kg, IV), whereas Inj(2-6) elicited progressively smaller responses such that inj(6) elicited minor responses. The vasodilator responses elicited by the endothelium-dependent agonist, acetylcholine, were markedly attenuated in L-NAME-treated rats that had received inj(1-6) of FAD but not in saline-treated rats that had received inj(1-6) of FAD. The vasodilator actions of L-S-nitrosocysteine and the NO donor, sodium nitroprusside, were not diminished after the injections of FAD in saline- or in L-NAME-treated rats. Binding studies demonstrated that the densities of muscarinic M3 receptors were increased in thoracic aorta endothelium of rats treated with L-NAME + inj(1-6) of saline or L-NAME + inj(1-6) of FAD as compared to rats treated with saline + inj(1-6) of saline or saline + inj(1-6) of FAD. The progressive loss of response to injections of FAD in L-NAME-treated rats coupled with the loss of response to acetylcholine suggests that FAD elicits the use-dependent depletion of vesicular pools of nitrosyl factors in endothelial cells that cannot be replenished in the absence of NO synthesis.