The study investigated the role of α2-adrenergic receptors of the caudal raphe region in the sympathetic and cardiovascular responses to the acute intermittent hypercapnia (AIHc). Urethane-anesthetized, vagotomized, mechanically ventilated Sprague-Dawley rats (n=38) were exposed to the AIHc protocol (5×3 min, 15 % CO2+50 % O2) in hyperoxic background (50 % O2). α2-adrenergic receptor antagonist-yohimbine was applied intravenously (1 mg/kg, n=9) or microinjected into the caudal raphe region (2 mM, n=12) prior to exposure to AIHc. Control groups of animals received saline intravenously (n=7) or into the caudal raphe region (n=10) prior to exposure to AIHc. Renal sympathetic nerve activity (RSNA), mean arterial pressure (MAP) and heart rate (HR) were monitored before exposure to the AIHc protocol (T0), during five hypercapnic episodes (THc1-5) and at 15 min following the end of the last hypercapnic episode (T15). Following intravenous administration of yohimbine, RSNA was significantly greater during THc1-5 and at T15 than in the control group (P<0.05). When yohimbine was microinjected into the caudal raphe region, AIHc elicited greater increases in RSNA during THc1-5 when compared to the controls (THc1: 138.0±4.0 % vs. 123.7±4.8 %, P=0.032; THc2: 137.1±5.0 % vs. 124.1±4.5 %, P=0.071; THc3: 143.1±6.4 % vs. 122.0±4.8 %, P=0.020; THc4: 146.1±6.2 % vs. 120.7±5.7 %, P=0.007 and THc5: 143.2±7.7 % vs. 119.2±7.2 %, P=0.038). During THc1-5, significant decreases in HR from T0 were observed in all groups, while changes in MAP were observed in the group that received yohimbine intravenously. These findings suggest that blockade of the α2-adrenegic receptors in the caudal raphe region might have an important role in sympathetic responses to AIHc.
a1_Plehniella Szidat, 1951 is emended based on new collections from South American long-whiskered catfishes. It is clearly differentiated from Sanguinicola Plehn, 1905 by lacking lateral tegumental body spines and by having 6 asymmetrical caeca. Plehniella sabajperezi sp. n. infects body cavity of Pimelodus albofasciatus (Mees) from the Demerara and Rupununi Rivers (Guyana) and Pimelodus blochii (Valenciennes) from Lake Tumi Chucua (Bolivia) and Napo River (Peru). It differs from Plehniella coelomicola Szidat, 1951 (type species) by having a thin-walled vas deferens that greatly exceeds the length of cirrus-sac and that joins the cirrus-sac at level of ovovitelline duct and ootype, an internal seminal vesicle that is absent or diminutive, and a cirrus-sac that is spheroid, nearly marginal, and envelops the laterally-directed distal portion of the male genitalia. Plehniella armbrusteri sp. n. infects body cavity of P. blochii from Lake Tumi Chucua (Bolivia). It differs from P. coelomicola and P. sabajperezi by having a relatively ovoid body, a massive intestine comprising caeca that are deeply-lobed to diverticulate and terminate in the posterior half of the body, a testis that flanks the distal tips of the posteriorly-directed caeca, and a proximal portion of the vas deferens that loops ventral to the testis. Small adults (Plehniella sp.) collected from body cavity of Pimelodus grosskopfii (Steindachner) from Cienega de Jobo and Canal del Dique (Colombia) differ from congeners by having a posteriorly-constricted body region, an anterior sucker with concentric rows of minute spines, an elongate anterior oesophageal swelling, short and wide caeca, and a male genital pore that opens proportionally more anteriad., a2_This study nearly doubles the number of aporocotylids documented from South America Rivers and comprises the first record of a fish blood fluke from P. blochii, P. albofasciatus and P. grosskopfii as well as from Bolivia, Colombia, Guyana or Peru., Raphael Orélis-Ribeiro, Stephen A. Bullard., and Obsahuje bibliografii
a1_Coeuritrema Mehra, 1933, previously regarded as a junior subjective synonym of Hapalorhynchus Stunkard, 1922, herein is revised to include Coeuritrema lyssimus Mehra, 1933 (type species), Coeuritrema rugatus (Brooks et Sullivan, 1981) comb. n., and Coeuritrema platti Roberts et Bullard sp. n. These genera are morphologically similar by having a ventral sucker, non-fused caeca, two testes, a pre-testicular cirrus sac, an intertesticular ovary, and a common genital pore that opens dorsally and in the sinistral half of the body. Phylogenetic analysis of the D1-D3 domains of the nuclear large subunit ribosomal DNA (28S) suggested that Coeuritrema and Hapalorhynchus share a recent common ancestor. Coeuritrema is morphologically most easily differentiated from Hapalorhynchus by having ventrolateral tegumental papillae and a definitive metraterm that is approximately 3-7× longer than the uterus. Coeuritrema comprises species that reportedly infect Asiatic softshell turtles (Testudines: Trionychidae) only, whereas Hapalorhynchus (as currently defined) comprises blood flukes that reportedly infect those hosts plus North American musk turtles (Sternotherus Bell in Gray) and mud turtles (Kinosternon Spix), both Kinosternidae, North American snapping turtles (Chelydridae), Asiatic hard-shelled turtles (Geoemydidae) and African pleurodirans (Pelomedusidae). Coeuritrema platti sp. n. infects the blood of Chinese softshell turtles, Pelodiscus sinensis (Wiegmann), cultured in the Da Rang River Basin (Phu Yen Province, Vietnam). It differs from C. lyssimus by having a narrow hindbody (< 1.6× forebody width), ventrolateral tegumental papillae restricted to the hindbody, a short cirrus sac (< 10% of corresponding body length), a transverse ovary buttressing the caeca, a short, wholly pre-ovarian metraterm (~ 10% of corresponding body length), and a submarginal genital pore., a2_It differs from C. rugatus by having small ventrolateral tegumental papillae, testes without deep lobes, and a Laurer's canal pore that opens posterior to the vitelline reservoir and dorsal to the oviducal seminal receptacle. The new species is only the second turtle blood fluke reported from Vietnam., Jackson R. Roberts, Raphael Orélis-Ribeiro, Binh T. Dang, Kenneth M. Halanych, Stephen A. Bullard., and Obsahuje bibliografii
The agonists of α2-adrenergic receptors such as clonidine, rilmenidine or monoxidine are known to lower blood pressure (BP) through a reduction of brain sympathetic outflow but their chronic antihypertensive effects in rats with low-renin or highrenin forms of experimental hypertension were not studied yet. Moreover, there is no comparison of mechanisms underlying BP reduction elicited by chronic peroral (po) or intracerebroventricular (icv) clonidine treatment. Male salt-sensitive Dahl rats fed a high-salt (4% NaCl) diet and Ren-2 transgenic rats were treated with clonidine administered either in the drinking fluid (0.5 mg/kg/day po) or as the infusion into lateral brain ventricle (0.1 mg/kg/day icv) for 4 weeks. Basal BP and the contributions of renin-angiotensin system (captopril 10 mg/kg iv) or sympathetic nervous system (pentolinium 5 mg/kg iv) to BP maintenance were determined in conscious cannulated rats at the end of the study. Both peroral and intracerebroventricular clonidine treatment lowered BP to the same extent in either rat model. However, in both models chronic clonidine treatment reduced sympathetic BP component only in rats treated intracerebroventricularly but not in perorally treated animals. In contrast, peroral clonidine treatment reduced angiotensin IIdependent vasoconstriction in Ren-2 transgenic rats, whereas it lowered residual blood pressure in Dahl rats. In conclusions, our results indicate different mechanisms of antihypertensive action of clonidine when administered centrally or systemically.
Mesembryanthemum crystallinum is an annual succulent plant that is being used as an emerging healthy leafy vegetable. To investigate the growth and physiological response of M. crystallinum to artificial lighting, five different light treatments were applied at 150 µmol(photon) m-2 s-1, which were white (W), different rations of red/blue (B) (15, 40, and 70%B), and blue (100%B), respectively. Our results showed that plants could gain as much as edible leaf area and dry mass with a certain ratio of blue (40%) in comparison with W. Plants grown under 100%B resulted in reduced photosynthetic rate, leaf area, and fresh mass compared with W. Adding blue fraction in the light regime enhanced the photosynthetic performance by influencing the amount of chlorophyll (Chl), Chl a/b, and specific leaf area. Under red/blue treatments, the electron transport rate and effective quantum yield of both PSII and PSI increased, while the nitrate content was reduced and flavonoids and total antioxidant capacity were unaffected.