Temporal variation in the concentrations and profiles of paralytic shellfish toxins and tetrodotoxin in scallop (Mizuhopecten yessoensis) and bloody clam (Anadara broughtonii) collected from the coast of Miyagi Prefecture, Japan.

For food safety, the concentrations and profiles of paralytic shellfish toxins (PSTs) and tetrodotoxin were examined in economically important scallops and bloody clams collected from the coast of the Miyagi Prefecture, Japan. PSTs were the major toxins in both species. The tetrodotoxin concentration in scallops increased in summer, although the highest value (18.7 µg/kg) was lower than the European Food Safety Authority guideline threshold (44 µg/kg). This confirmed the safety for tetrodotoxin in this area.

Synthesis and Identification of decarbamoyloxySaxitoxins in Toxic Microalgae and their Reactions with the Oxygenase, SxtT, Reveal Saxitoxin Biosynthesis.

Saxitoxin (STX, 1) is a representative compound of paralytic shellfish toxins (PSTs) that are produced by marine dinoflagellates and freshwater cyanobacteria. Although several pathways have been proposed for the biosynthesis of STX, the order of ring and side chain hydroxylation, and formation of the tricyclic skeleton have not been well established. In this study, 12,12-dideoxy-decarbamoyloxySTX (dd-doSTX, 2), the most reduced STX analogue having the tricyclic skeleton, and its analogues, 12ß-deoxy-doSTX (12ß-d-doSTX, 3), 12α-deoxy-doSTX (12α-d-doSTX, 4), and doSTX (5), were synthesized, and these compounds were screened in the toxic microalgae using high-resolution LCMSMS. dd-doSTX (2) and 12ß-d-doSTX (3) were identified in the PSTs-producing dinoflagellates (Alexandrium catenella, A. pacificum, and/or Gymnodinium catenatum) and in the cyanobacterium Dolichospermum circinale (TA04). doSTX (5), previously isolated from the dinoflagellate G. catenatum, was also identified in D. circinale (TA04). Furthermore, the conversion of 2 to 3, and 4 to 5, by SxtT with VanB, a reported Rieske oxygenase and its redox partner in STX biosynthesis, was confirmed. These results support that 2 is a possible biosynthetic precursor of STX, and that ring and side-chain hydroxylations proceed after cyclization.

Association between dynapenia and cognitive decline in community-dwelling older Japanese adults: The IRIDE Cohort Study.

AIM: Muscle mass and strength correlate with cognitive function; however, it remains unclear whether dynapenia (i.e., muscle weakness with preserved muscle mass) is relevant. This study aimed to explore whether dynapenia is associated with global cognitive function in community-dwelling older Japanese adults. METHODS: This cross-sectional study used data from the Integrated Research Initiative for Living Well with Dementia Cohort Study, which pooled data from five community-based geriatric cohorts. Dynapenia was defined as muscle weakness without muscle mass loss according to the Asian Working Group for Sarcopenia criteria. Cognitive function was assessed using the Mini-Mental State Examination (MMSE). An ordered logistic regression analysis was conducted with dynapenia as the exposure and with cognitive decline stages, defined as an MMSE score of 27-30 for normal cognition, 24-26 for possible cognitive decline, and <24 for cognitive decline, as the outcome, stratified by sex and adjusted for age, muscle mass, education, alcohol consumption, smoking habits, living alone, and non-communicable diseases. RESULTS: We analyzed data for 3338 participants (2162 female) with preserved muscle mass. Of these, 449 (13.5%) had dynapenia, and 79 (2.4%) exhibited cognitive decline. Multivariate odds ratios (95% confidence interval) for cognitive decline among those with dynapenia, compared with those without dynapenia, were 1.51 (1.02-2.24) for males and 2.08 (1.51-2.86) for females. CONCLUSIONS: Muscle weakness is associated with cognitive decline, even in individuals with preserved muscle mass. Further studies are needed to better understand the association between muscle weakness and cognitive decline over time in order to develop dementia prevention strategies for those with dynapenia. Geriatr Gerontol Int 2024; 24: 123-129.

Inaccessibility, unresponsiveness, inconsistency, and invisibility of informal caregivers of older persons with cognitive impairment: community-based participatory research.

BACKGROUND: Studies on informal caregivers in Japan have been limited to family caregivers and largely conducted where family caregivers generally gather. Family caregivers who do not visit such places or non-family caregivers are generally overlooked, and data on these informal caregivers remains scant. Consequently, a framework is needed through which healthcare professionals can approach the informal caregivers of community-dwelling older persons. Therefore, this study approaches such informal caregivers and proposes a classification system for them from the starting point of older persons living in the community with cognitive impairment. METHODS: In 2016, we conducted an epidemiological survey of 7000 + community-dwelling older persons and identified 198 residents with Mini-mental state examination scores less than 23. A team of healthcare professionals contacted them regularly. By 2022, 92 people were still living in the community, and we systematically asked them about their informal caregivers. After approaching the caregivers and obtaining informed consent, we mailed separate questionnaires to older persons and informal caregivers. RESULTS: Among the caregivers, 59%, 34%, and 3% were the child, spouse, and sibling of the older person, while the remaining 4% were non-family caregivers. Except for two daughters-in-laws, all children were biological children of the older person. Male caregivers (46%) tended to have full-time jobs, whereas female caregivers (54%) tended to face financial difficulties. Only 3% of the caregivers had joined a family caregivers' association. Caregivers' reason for not joining such organizations was a lack of time and knowledge. A 3-tiered classification system was developed for these informal caregivers: (1) the household form, (2) accessibility, and (3) the reciprocal awareness of caregiving. Furthermore, family caregivers who lived with the older person or visited them more than once a week with reciprocal awareness of caring and being cared, or "traditional caregivers," accounted for 68% of the caregivers in this study. CONCLUSION: Core family caregivers can be easily approached at places where such caregivers generally gather. However, there also exists a group of informal caregivers who are sometimes inaccessible, unresponsive, and invisible to healthcare professionals. Moreover, their awareness of caregiving is sometimes inconsistent.

The relationship between working status in old age and cause-specific disability in Japanese community-dwelling older adults with or without frailty: A 3.6-year prospective study.

AIM: To examine the effects of employment engagement, classified by frailty and working status, on the incidence of disability in urban community-dwelling older adults. METHODS: We used data from 6386 initially nondisabled residents aged 65-84 years from Ota City, Tokyo, Japan, in 2016. The observation duration was 3.6 years. Self-administered questionnaires applied the Cox proportional hazard model by assessing the existence of frailty through Check-List 15 (with a score ≥4 indicating the state of frailty), controlling for age, sex, living situation, education level, equivalent income, chronic conditions, body mass index, instrumental activities of daily living, self-rated health, drinking and smoking status, and social activities. We evaluated the predictive value of working status (full-time, part-time, temporary, or nonworker) at baseline for cause-specific disability (dementia-type vs. non-dementia-type) incidence, identified using the long-term care insurance system's nationally unified database. RESULTS: Of the 6386 participants, 806 (63/1134 full-time workers; 58/1001 part-time workers; 61/547 temporary workers; 624/3704 nonworkers) presented with disabilities during the 3.6-year-long duration. Adjustments for conventional covariates showed that nonfrail full-time and part-time workers, as well as frail full-time workers, had significantly lower risks of all-cause disability incidence. Furthermore, nonfrail and frail full-time workers had significantly lower risks of dementia-type and nondementia-type disabilities, respectively. CONCLUSIONS: The incidence of disability in older adults was influenced by working and frailty status. Engaging in full-time work thus prevents disabilities in older adults, regardless of their frailty status. Meanwhile, nonfrail older adults are able to avoid disabilities even when engaging in part-time work. Geriatr Gerontol Int 2023; 23: 855-863.

[The expected role of Dementia Support Doctors in dealing with complex cases of older people with dementia].

AIM: The present studyinvestigated the roles expected of Dementia Support Doctors (DSDs) in dealing with complex cases. METHODS: The participants were attendees of the education programs organised by the Center for Promoting Dementia Support and the Medical Center for Dementia at the Tokyo Metropolitan Geriatric Hospital from April 2021 to March 2022. A self-administered postal questionnaire survey was conducted. The questionnaire included items on the basic attributes of the participants, their experiences with the issues associated with complex cases, and role expectations of consulting/collaboration partners when dealing with complex cases. RESULTS: The valid response rate was 49.3%. DSDs were expected by primary physicians, Community General Support Center staff and administrative staff to diagnose dementia and give advice on support strategies for complex cases. Primary physicians further expected them to initiate pharmacotherapy with anti-dementia drugs and address the pharmacotherapy needs for managing Behavioral and Psychological Symptoms of Dementia. It was also found that DSDs' experience with complex cases was comparable to that of the staff at the Medical Centers for Dementia. Of note, DSDs were mentioned less frequently as consulting/collaboration partners than Medical Centers for Dementia and primary physicians. CONCLUSIONS: The study showed that DSDs play an important role in dealing with complex cases. The roles of DSDs and ways to collaborate with them need to be communicated through interprofessional education.

Fluctuations in Cognitive Test Scores and Loss to Follow-Up in Community-Dwelling Older Adults: The IRIDE Cohort Study.

INTRODUCTION: We examined the relationship between previous fluctuations in Mini-Mental State Examination (MMSE) scores, future changes in MMSE scores, and attrition from follow-up surveys, which helps in a more comprehensive interpretation of repeatedly collected MMSE scores. METHODS: This 4-year longitudinal study included 2,073 community-dwelling older adults aged ≥65 years in Japan. The MMSE was administered at baseline (T0), 2 years (T1), and 4 years (T2) follow-up. We performed multinomial logistic regression analysis with the dependent variable, indicating the change in MMSE score from T1 to T2 (categorized as increase, no change [reference category], and decrease) and attrition at T2. The independent variables included the change in MMSE scores from T0 to T1 and MMSE scores at T0 and T1. RESULTS: The mean MMSE score was 29 across the three time points. A one-point decrease in MMSE score from T0 to T1 was associated with 79% (95% confidence interval: 1.62, 1.97) higher odds of an increase in MMSE score from T1 to T2 and 28% (1.17, 1.40) higher odds of attrition at T2. A one-point decrement in the MMSE score at T0 and T1 was also associated with an increase in the MMSE score from T1 to T2 and attrition at T2. CONCLUSION: Focusing on cognitive fluctuation for 2 years, rather than cognitive function at a point in time, would have no remarkable advantage when focusing on future cognitive function and attrition. Our results emphasize the need for further studies to identify factors that distinguish between those who continue to attend follow-up surveys and show improvements in cognitive test scores and those who drop out.

Approaches to Construction of the Medium-Sized Ring Structure in Zetekitoxin AB by Ring-Closing Metathesis.

Zetekitoxin AB (ZTX), a member of the saxitoxin (STX) family isolated from the Panamanian golden frog Atelopus zeteki, shows extremely potent NaV-inhibitory activity. Here, we investigate the synthesis of 12-membered ring structure with the C11 tertiary hydroxyl group in ZTX by means of the Mislow-Evans rearrangement reaction and subsequent ring-closing metathesis reaction. Although this approach did not provide access to the 12-membered macrocycle, we obtained a new STX analog with an 18-membered macrolactam structure as a synthetic mimic of ZTX.

Age- and sex-specific associations between sarcopenia severity and poor cognitive function among community-dwelling older adults in Japan: The IRIDE Cohort Study.

Introduction: This study examined whether the association between sarcopenia severity and cognitive function differed according to sex and age in community-dwelling older adults in Japan. Methods: This is a cross-sectional study of older adults (age ≥ 65 years) consisting of five regional cohorts integrated as the Integrated Research Initiative for Living Well with Dementia (IRIDE) Cohort Study. Sarcopenia severity was determined based on the Asian Working Group for Sarcopenia 2019, which assessed grip strength, walking speed, and skeletal muscle mass index. Poor cognitive function was defined as a Mini-Mental State Examination score of ≤ 23. Odds ratios (ORs) and 95% confidence intervals (CIs) for poor cognitive function were calculated by sex and age group (65-74 and ≥75 years) using binomial logistic regression models, which were adjusted for age, educational attainment, history of non-communicable diseases, smoking and drinking habits, living alone, frequency of going outdoors, exercise habits, and depressive symptom. Results: Of the 8,180 participants, 6,426 (1,157 men aged 65-74 and 1,063 men aged 75 or older; 2,281 women aged 65-74 and 1,925 women aged 75 or older) were analyzed. The prevalence ratio of sarcopenia and severe sarcopenia were 309 (13.9%) and 92 (4.1%) among men and 559 (13.3%) and 166 (3.7%) among women, respectively. A total of 127 (5.8%) men and 161 (3.9%) women had a poor cognitive function. Setting non-sarcopenia as a reference, the adjusted ORs (95% CI) of poor cognitive function were 2.20 (1.54, 3.15) for sarcopenia and 3.56 (2.20, 5.71) for severe sarcopenia. A similar trend was observed in analyses stratified by sex and age, with linear associations (P for trend <0.05) in both categories. Furthermore, there was a significant interaction (P < 0.05) between sex and sarcopenia severity, indicating a stronger linear association of sarcopenia severity with poor cognitive function in women compared with men. Discussion and conclusion: Sarcopenia severity was linearly associated with poor cognitive function in adults aged ≥ 65 years, with a stronger association in women compared with men.

Characteristics of people seeking consultation after progressing to severe dementia: A mixed-method analysis.

OBJECTIVES: This explores the characteristics of patients with worsening dementia who did not receive a specialized medical examination or care. METHODS: This study utilized a mixed methods analysis. Of the 2712 people who received the Mini Mental State of Examination (MMSE) at the Community Consultation Center for Citizens with MCI and Dementia between December 2007 and December 2019, 1413 people who scored 23 points or less were included. Participants were categorized into mild, moderate, and severe groups, based on their MMSE scores. Participants' characteristics-gender, age, presence or absence of an escort, demographics, family type, and presence or absence of a family doctor-were compared between the groups. To further understand the severe group's characteristics, clinical psychologists recorded consultation forms were categorized. RESULTS: More than 80% of the patients in each group had a family doctor. Moreover, all the severe groups had escorts, and the role of family members and supporters was important for the consultation. In the severe group, 29 patients had never received specialized medical care. Their characteristics were coded "non-existence" (fewer people or opportunities to notice their needs), "connection failure" (a lack of access or connections to consultations), and "evaluation failure" (not recognized as a problem requiring consultation). CONCLUSIONS: It is necessary to improve primary physician education, disseminate knowledge, and raise awareness about dementia, besides building and strengthening networks to alleviate the isolation of dementia patients and their families. The psychological aspects of family members' denial regarding their family members with dementia must be addressed through intervention.

The quite low cross-reactivity of Kawatsu's anti-tetrodotoxin monoclonal antibody to 5,6,11-trideoxytetrodotoxin, 11-nortetrodotoxin-6(S)-ol, and 11-oxotetrodotoxin, the major tetrodotoxin analogues in pufferfish.

The monoclonal antibody against tetrodotoxin (TTX), prepared by Kawatsu et al. (1997), has been used in several TTX-related studies. Herein, we confirmed the quite low cross-reactivity of this antibody to three major TTX analogues in pufferfish using competitive ELISA: 5,6,11-trideoxyTTX (<2.2%), 11-norTTX-6(S)-ol (<0.3%), and 11-oxoTTX (<1.5%), with reactivity against TTX being 100%. We further confirmed that the presence of these analogues did not cause a marked overestimation of TTX in pufferfish extracts using competitive ELISA.

Metabolic inhibitor induces dynamic changes in saxitoxin biosynthesis and metabolism in the dinoflagellate Alexandrium pacificum (Group IV) under in vivo labeling condition.

In paralytic shellfish toxin-producing dinoflagellates, intracellular levels of saxitoxin and its analogues (STXs) are controlled by a balance between degradation and biosynthesis in response to marine environmental fluctuations and stresses. The purpose of this study was to demonstrate the utility of statistical analysis of in vivo labeling data for the dynamic analysis of variations in toxin production under stress. A toxic strain of the dinoflagellate Alexandrium pacificum (Group IV) was cultured in colchicine-containing 15N-labeled sodium nitrate-medium and metabolite levels were analyzed over time by liquid chromatography-mass spectrometry. Quantitative values of all isotopomers of precursor amino acids, biosynthetic intermediates, and major STXs were subjected to statistical analysis. The decrease of the nitrogen incorporation rates for all compounds suggested that colchicine decreased nitrate assimilation upstream of glutamate biosynthesis. In colchicine-treated cultures, the per-cell content of total STX analogues did not change significantly over time; however, the production rate of each pathway varied greatly. De novo STX biosynthesis was decreased by colchicine until Day 3, while the salvage pathway was not. Subsequently, biosynthesis by both pathways was enhanced. This analysis of dynamic metabolism provides new insights into the complex mechanisms regulating STX metabolism in dinoflagellates.

Modifiable healthy behaviours and incident disability in older adults: Analysis of combined data from two cohort studies in Japan.

Healthy behaviours reduce the risk of incident disability; however, their components require further consideration. Specifically, little evidence exists on healthy behaviours that comprise modifiable factors, including social aspects, and their effects on those who do not engage in them. This study aimed to examine the association between engaging in healthy behaviours with modifiable factors and incident disability among community-dwelling older adults; as well as identify factors associated with nonengagement in healthy behaviours. We analysed data obtained from 1357 older adults aged 65 years and more without disabilities at baseline. The outcome was incident disability, which was defined based on the long-term care insurance certification in Japan. This study included regular exercise (≥1 day/week), favourable eating habits (≥4 dietary variety score), and social participation (engaging in two or more social activities) as components of healthy behaviours. We used the Cox proportional hazards model to calculate hazard ratios (HR) for incident disabilities. The proportion of those who satisfied all healthy behaviours was 21 %. During the follow-up period (median: 6.3 years), 282 incident disabilities were confirmed. Compared to those who engaged in one healthy behaviour, those who satisfied all healthy behaviours showed a 31 % (95 % confidence interval: 0.48, 0.98) lower HR of incident disability after adjusting for covariates. Current smoking and depressive mood were associated with non-engagement in healthy behaviours. This study found that having physically and socially active lifestyles and favourable eating habits are effective in reducing the risk of incident disability. Meanwhile, several older adults lack the components of a healthy lifestyle. Approaches that focus on multiple healthy behaviours are necessary to enhance the benefits of healthy lifestyles.

GO Revisited: Qualitative Analysis of the Motivating Factors to Start and Continue Playing GO.

PURPOSE: To explore the motivating factors for starting and continuing to play GO among older adults, as well as to examine the effect of GO activities in helping people to live well with, as well as to prevent, dementia. DESIGN: Qualitative descriptive research. METHODS: Semi-structured interviews were conducted. FINDINGS: The participants reportedly started playing GO for dementia prevention, and to cope with their anxieties about aging. They described feeling relaxed while playing GO. They also felt that playing GO fostered human relationships. CONCLUSIONS: GO is effective in assisting older adults to cope with aging issues, cultivate peace of mind and encourage interaction with peers. CLINICAL EVIDENCE: GO is effective in assisting older adults to cope with aging issues, cultivate peace of mind and encourage interaction with peers.

Role of personality traits in determining the association between social participation and mental health: A cross-sectional study in Japan.

The role of personality in determining the association between social participation and mental health was examined by a cross-sectional study. We analyzed data from 4981 older adults aged 65-84 years who were recruited via a mail survey in one region of Japan. We defined poor mental health using a score ≤12 points on the World Health Organization-Five Well-Being Index-Japanese. Personality traits were measured by 10 Item Personality Inventory-Japanese. In women, higher openness positively moderated the association between private group participation (volunteering, sports, hobby, and learning) and mental health, while higher neuroticism negatively moderated it. This study contributes to knowledge about mental health, personality, and participation. The findings provide provisional evidence about recommending private group participation for women with high openness but not those with high neuroticism.

Combined Impacts of Physical Activity, Dietary Variety, and Social Interaction on Incident Functional Disability in Older Japanese Adults.

BACKGROUND: This 3.6-year prospective study examined combined impacts of physical activity, dietary variety, and social interaction on incident disability and estimated population-attributable fraction for disability reduction in older adults. METHODS: Participants were 7,822 initially non-disabled residents (3,966 men and 3,856 women) aged 65-84 years of Ota City, Tokyo, Japan. Sufficiency of moderate-to-vigorous-intensity physical activity (MVPA) ≥150 min/week, dietary variety score (DVS) ≥3 (median), and social interaction (face-to-face and/or non-face-to-face) ≥1 time/week was assessed using self-administered questionnaires. Disability incidence was prospectively identified using the long-term care insurance system's nationally unified database. RESULTS: During a follow-up of 3.6 years, 1,046 (13.4%) individuals had disabilities. Independent multivariate-hazard ratios (HRs) and 95% confidence intervals (CIs) of MVPA, DVS, and social interaction sufficiency for incident disability were 0.68 (95% CI, 0.59-0.78), 0.87 (95% CI, 0.77-0.99), and 0.90 (95% CI, 0.79-1.03), respectively. Incident disability HRs gradually reduced with increased frequency of satisfying these behaviors (any one: HR 0.82; 95% CI, 0.65-1.03; any two: HR 0.65; 95% CI, 0.52-0.82; and all three behaviors: HR 0.54; 95% CI, 0.43-0.69), in an inverse dose-response manner (P < 0.001 for trend). Population-attributable fraction for disability reduction in satisfying any one, any two, and all three behaviors were 4.0% (95% CI, -0.2 to 7.9%), 9.6% (95% CI, 4.8-14.1%), and 16.0% (95% CI, 8.7-22.8%), respectively. CONCLUSION: Combining physical activity, dietary variety, and social interaction substantially enhances the impacts on preventing disability among older adults, with evidence of an inverse dose-response manner. Improving insufficient behavior elements through individual habits and preexisting social group activities may be effective in preventing disability in the community.

Meaning of death among care workers of geriatric institutions in a death-avoidant culture: Qualitative descriptive analyses of in-depth interviews by Buddhist priests.

OBJECTIVE: Care workers' views of clients' death have not been explored in Japan because of a cultural tendency to avoid talking openly about death. However, given the arising problems in end-of-life care settings, such as abuse and burnout, understanding care workers' views regarding death is essential for designing effective interventions. We had two main research questions: Do care workers in Japan have their own ideas about death after working in the landscape of dying and death? Do these ideas influence care workers' professional lives? METHODS: We recruited interviewees based on a quantitative survey of care workers at 10 geriatric institutions in Tokyo. Among the 323 respondents, 23 survey respondents were willing to participate in an interview. After the scheduling process, nine individuals were able to participate in an in-depth interview. To overwhelm cultural avoidance regarding death that prevents care workers from talking openly about death, Buddhist priests conducted interviews in the current study. Physicians and researchers assisted the interviews. Because this was exploratory studies in which little is known about the topic in question, we adapted a qualitative descriptive approach. FINDINGS: Thematic analysis revealed that: 1) care workers had clear views about conditions of clients' good death after working in the field of dying and death; 2) care workers were motivated by past experiences of being close to dying themselves; and 3) care workers regarded their care for the dying as an experience that enriched their lives. In addition, the results revealed that the concept of spiritual care in Japan is still its infancy among care workers because of its vague definition. CONCLUSIONS: Care workers were willing to work for dying people with their view of death, and regarded their jobs as important opportunities for personal growth through caring for the dying.

State-Dependent Inhibition of Voltage-Gated Sodium Channels in Neuroblastoma Neuro-2A Cells by Arachidonic Acid from Halichondria okadai.

Voltage-gated sodium channels (Nav) are closely associated with epilepsy, cardiac and skeletal muscle diseases, and neuropathic pain. Several toxic compounds have been isolated from the marine sponge Halichondria okadai; however, toxic substances that modulate Nav are yet to be identified. This study aimed to identify Nav inhibitors from two snake venoms and H. okadai using mouse neuroblastoma Neuro-2A cells (N2A), which primarily express the specific Nav subtype Nav1.7, using whole-cell patch-clamp recordings. We successfully isolated arachidonic acid (AA, 1) from the hexane extract of H. okadai, and then the fatty acid-mediated modulation of Nav in N2A was investigated in detail for the first time. Octanoic acid (2), palmitic acid (3), and oleic acid (4) showed no inhibitory activity at 100 µM, whereas AA (1), dihomo-γ-linolenic acid (DGLA, 5), and eicosapentaenoic acid (EPA, 6) showed IC50 values of 6.1 ± 2.0, 58 ± 19, and 25 ± 4.0 µM, respectively (N = 4, mean ± SEM). Structure and activity relationships were investigated for the first time using two ω-3 polyunsaturated fatty acids (PUFAs), EPA (6) and eicosatetraenoic acid (ETA, 7), and two ω-6 PUFAs, AA (1) and DGLA (5), to determine their effects on a resting state, activated state, and inactivated state. Steady-state analysis showed that the half inactivation potential was largely hyperpolarized by 10 µM AA (1), while 50 µM DGLA (5), 50 µM EPA (6), and 10 µM ETA (7) led to a slight change. The percentages of the resting state block were 24 ± 1, 22 ± 1, 34 ± 4, and 38 ± 9% in the presence of AA (1), DGLA (5), EPA (6), and ETA (7), respectively, with EPA (6) and ETA (7) exhibiting a greater inhibition than both AA (1) and DGLA (5), and their inhibitions did not increase in the following depolarization pulses. None of the compounds exhibited the use-dependent block. The half recovery times from the inactivated state for the control, AA (1), DGLA (5), EPA (6), and ETA (7) were 7.67 ± 0.33, 34.3 ± 1.10, 15.5 ± 1.10, 10.7 ± 0.31, and 3.59 ± 0.18 ms, respectively, with AA (1) exhibiting a distinctively large effect. Overall, distributed binding to the resting and the inactivated states of Nav would be significant for the inhibition of Nav, which presumably depends on the active structure of each PUFA.