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The ventral part of the medulla, which contains important cardiovascular regions, is reportedly activated during exercise. Nevertheless, it was uncertain which region(s) in the ventral medulla are specifically activated by exercise. The present study aimed to demonstrate a general pattern of exercise-specific distribution of excited neuronal cells in the rat ventral medulla. Via immunohistochemical experiments, we mapped tyrosine hydroxylase- and Fos-immunoreactive cells (TH-IR and Fos-IR cells, respectively) on rat medullary coronal sections following a bout of voluntary treadmill exercise, a comparative control period, or after pharmacologically induced-hypotension under anesthesia. In the ventral medulla at the rostrocaudal level adjacent, but not rostral or caudal, to the caudal edge of the facial nucleus, voluntary treadmill exercise induced significant (P < 0.05) increases in Fos expression, similar to hypotension. The rostral ventrolateral medulla (RVLM), as compared with the rostral ventromedial medulla (RVMM), displayed a greater number of Fos-IR cells due to either exercise or hypotension. In the RVLM, either exercise or hypotension induced significant expression of Fos in both TH-IR and TH non-immunoreactive cells. In the caudal ventrolateral medulla (CVLM), hypotension, but not exercise, increased the ratio of Fos-IR cells in the TH-IR population. These findings demonstrate that RVLM adrenergic and non-adrenergic neurons are specifically excited by voluntary exercise in rats, while RVMM or CVLM neurons are not. We suggest that RVLM C1/non-C1 neurons are a major part of central circuitries underlying sympathetic adjustments to exercise. [ABSTRACT FROM AUTHOR]

Abstract: In Japanese rivers, there is a serious conflict between the great cormorant (Phalacrocorax carbo hanedae) and fisheries. The basis of this conflict is that the cormorants feed on ayu (Plecoglossus altivelis), a commercially important fish that is stocked primarily for recreational fishing. To understand how cormorants alter their foraging habitats in relation to the stocked fish and fishing activities, we examined the relationship between cormorant abundance and ayu biomass during the cormorant breeding season (from April to July) using two approaches that differ in spatial scale. First, we compared cormorant numbers in different river sections that were defined based on ayu stocking. The cormorant numbers in the sections stocked with ayu increased during the ayu release period, whereas the cormorant numbers in other sections showed no clear seasonal patterns. Second, we tested whether cormorant numbers were correlated with the biomass of ayu caught with cast nets. Positive correlations were observed between the biomass of ayu and the number of cormorants that were within 900m, 1km, or 2km of fish sampling points; however, such correlations were not observed within 100–800m of the sampling points. The biomass of ayu caught with cast nets increased steadily from April to June despite predation by cormorants; however, this biomass decreased sharply in July when the fishing season opened. This study indicates that although cormorants altered their feeding areas in accordance with the mass stocking of ayu in a Japanese river, sufficient numbers of ayu were still maintained for anglers. [Copyright &y& Elsevier]

Key points: Causal relationships between central cardiovascular pathways and sympathetic vasomotor tone have not been evidenced. This study aimed to verify the sympathoexcitatory role of hypothalamic paraventricular nucleus neurons that project to the rostral ventrolateral medulla (PVN‐RVLM neurons). By using optogenetic techniques, we demonstrated that stimulation of PVN‐RVLM glutamatergic neurons increased renal sympathetic nerve activity and arterial pressure via, at least in part, stimulation of RVLM C1 neurons in rats. This monosynaptic pathway may function in acute sympathetic adjustments to stressors and/or be a component of chronic sympathetic hyperactivity in pathological conditions such as heart failure. Abstract: The rostral ventrolateral medulla (RVLM), which is known to play an important role in regulating sympathetic vasomotor tone, receives axonal projections from the hypothalamic paraventricular nucleus (PVN). However, no studies have proved that excitation of the PVN neurons that send axonal projections to the RVLM (PVN‐RVLM neurons) causes sympathoexcitation. This study aimed to directly examine the sympathoexcitatory role of PVN‐RVLM neurons. Male rats received microinjections into the PVN with an adeno‐associated virus (AAV) vector that encoded a hybrid of channelrhodopsin‐2/1 with the reporter tdTomato (ChIEF‐tdTomato), or into the RVLM with a retrograde AAV vector that encoded a channelrhodopsin with green fluorescent protein (ChR2‐GFPretro). Under anaesthesia with urethane and α‐chloralose, photostimulation (473 nm wavelength) of PVN‐RVLM neurons, achieved by laser illumination of either RVLM of ChIEF‐tdTomato rats (n = 8) or PVN of ChR2‐GFPretro rats (n = 4), elicited significant renal sympathoexcitation. Immunofluorescence confocal microscopy showed that RVLM adrenergic C1 neurons of ChIEF‐tdTomato rats were closely associated with tdTomato‐labelled, PVN‐derived axons that contained vesicular glutamate transporter 2. In another subset of anaesthetized ChIEF‐tdTomato rats (n = 6), the renal sympathoexcitation elicited by photostimulation of the PVN was suppressed by administering ionotropic glutamate receptor blockers into the RVLM. These results demonstrate that excitation of PVN‐RVLM glutamatergic neurons leads to sympathoexcitation via, at least in part, stimulation of RVLM C1 neurons. [ABSTRACT FROM AUTHOR]

The Fukushima Daiichi power plant accident led to large‐scale and long‐term evacuation zones in which usual land‐use activities such as farming have been stopped. In particular, the loss of irrigated rice paddies is hypothesized to have seriously impacted freshwater biodiversity. In 2014, we started acoustic monitoring of frogs by using digital voice recorders in and around the evacuation zone. For the monitoring project, 52 and 57 monitoring sites were located within schoolyards (including those that had been converted into community centers) to examine the frog assemblages in the urban and rural landscapes of the region in 2014 and 2015, respectively. At each site, a digital voice recorder was installed during the period from May to July, and we recorded 10 min a day at night using a timed‐recording mode. We divided the audio data into 20‐s segments and identified species recorded in segments sampled from late May to late June (partly in early July). We identified eight frog species from 1,962 audio segments in total (correspond to 4 days per year in principal). For each species, intensity of calling at four levels was also recorded as an index of abundance. We are continuing to monitor and intend to update the dataset with new observations hereafter. Our dataset will support scientists and experts in recognizing the status and dynamics of anuran assemblages in and around the evacuation zone and will contribute to the promotion of open science. The complete data set for this abstract published in the Data Paper section of the journal is available in electronic format in MetaCat in JaLTER at http://db.cger.nies.go.jp/JaLTER/metacat/metacat/ERDP-2020-12.1/jalter-en. [ABSTRACT FROM AUTHOR]

Large-scale land abandonment and reconstruction activity has altered the ecosystem structure in the evacuation area for the Fukushima Daiichi power plant accident in 2011. Despite social concerns about changes in the avian assemblages that occurred after the accident, publicly accessible data are quite limited. We engaged in acoustic monitoring of birds using digital voice recorders from 2014 in and around the Fukushima evacuation zone. All monitoring sites were located within schoolyards (including those that had been converted to community centers) to examine the bird assemblages in the urban and rural landscapes that were heavily altered by land abandonment due to the nuclear plant accident. A digital voice recorder was installed at each monitoring site during May-July, and we recorded 20 min a day using timer-recording mode. We divided the audio data into 1-min segments and identified species occurred in sampled segments by experts. These data represent the presence-absence records from 52 sites monitored in 2014. In 2014, we identified the species for 7138 segments in total and 68 species occurred. We are continuing to monitor and intend to update the dataset with new observations hereafter. Our dataset will help people to recognize the status and dynamics of avian assemblage inside the evacuation zone, and will contribute to promote open science in avian ecological studies. [ABSTRACT FROM AUTHOR]