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Haramura T, Ikegami T, Wong MKS, Takei Y. Preparatory Mechanisms for Salinity Tolerance in Two Congeneric Anuran Species Inhabiting Distinct Osmotic Habitats. Zoolog Sci 2019; 36:215-222. [PMID: 31251490 DOI: 10.2108/zs180091] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2018] [Accepted: 12/04/2018] [Indexed: 11/17/2022]
Abstract
Anurans occupy a wide variety of habitats of diverse salinities, and their osmoregulatory ability is strongly regulated by hormones. In this study, we compared the adaptability and hormonal responses to osmotic stress between two kajika frogs, Buergeria japonica (B.j.) and B. buergeri, (B.b.), which inhabit coastal brackish waters (BW) in the Ryukyu Islands and freshwater (FW) in the Honshu, respectively. Both hematocrit and plasma Na+ concentration were significantly higher in B.j. than in B.b. when both were kept in FW. After transfer to one-third seawater (simulating the natural BW environment), which is slightly hypertonic to their body fluids, their body mass decreased and plasma Na concentration increased significantly in both species. After transfer, plasma Na+ concentration increased significantly in both species. We examined the gene expression of two major osmoregulatory hormones, arginine vasotocin (AVT) and atrial natriuretic peptide (ANP), after partial cloning of their cDNAs. ANP mRNA levels were more than 10-fold higher in B.j. than in B.b. in FW, but no significant difference was observed for AVT mRNA levels due to high variability, although the mean value of B.j. was twice that of B.b. Both AVT and ANP mRNA levels increased significantly after transfer to BW in B.b. but not in B.j., probably because of the high levels in FW. These results suggest that B.j. maintains high plasma Na+ concentration and anp gene expression to prepare for the future encounter of the high salinity. The unique preparatory mechanism may allow B.j. wide distribution in oceanic islands.
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Affiliation(s)
- Takashi Haramura
- The Hakubi Center for Advanced Research, Kyoto University, Sakyo, Kyoto 606-8501, Japan,
| | - Taro Ikegami
- Department of Otorhinolaryngology, Head and Neck Surgery, Graduate School of Medicine, University of the Ryukyus, 207 Uehara, Nishihara, Okinawa 903-0215, Japan
| | - Marty K S Wong
- Laboratory of Physiology, Atmosphere and Ocean Research Institute, The University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa, Chiba 277-8564, Japan
| | - Yoshio Takei
- Laboratory of Physiology, Atmosphere and Ocean Research Institute, The University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa, Chiba 277-8564, Japan
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Wilczynski W, Quispe M, Muñoz MI, Penna M. Arginine Vasotocin, the Social Neuropeptide of Amphibians and Reptiles. Front Endocrinol (Lausanne) 2017; 8:186. [PMID: 28824546 PMCID: PMC5545607 DOI: 10.3389/fendo.2017.00186] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/29/2017] [Accepted: 07/18/2017] [Indexed: 12/04/2022] Open
Abstract
Arginine vasotocin (AVT) is the non-mammalian homolog of arginine vasopressin (AVP) and, like vasopressin, serves as an important modulator of social behavior in addition to its peripheral functions related to osmoregulation, reproductive physiology, and stress hormone release. In amphibians and reptiles, the neuroanatomical organization of brain AVT cells and fibers broadly resembles that seen in mammals and other taxa. Both parvocellular and magnocellular AVT-containing neurons are present in multiple populations located mainly in the basal forebrain from the accumbens-amygdala area to the preoptic area and hypothalamus, from which originate widespread fiber connections spanning the brain with a particularly heavy innervation of areas associated with social behavior and decision-making. As for mammalian AVP, AVT is present in greater amounts in males in many brain areas, and its presence varies seasonally, with hormonal state, and in males with differing social status. AVT's social influence is also conserved across herpetological taxa, with significant effects on social signaling and aggression, and, based on the very small number of studies investigating more complex social behaviors in amphibians and reptiles, AVT may also modulate parental care and social bonding when it is present in these vertebrates. Within this conserved pattern, however, both AVT anatomy and social behavior effects vary significantly across species. Accounting for this diversity represents a challenge to understanding the mechanisms by which AVT exerts its behavioral effects, as well are a potential tool for discerning the structure-function relationships underlying AVT's many effects on behavior.
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Affiliation(s)
- Walter Wilczynski
- Neuroscience Institute, Center for Behavioral Neuroscience, Georgia State University, Atlanta, GA, United States
- *Correspondence: Walter Wilczynski,
| | - Maricel Quispe
- Programa de Fisiología y Biofísica, Instituto de Ciencias Biomédicas, Facultad de Medicina, Universidad de Chile, Santiago, Chile
| | - Matías I. Muñoz
- Programa de Fisiología y Biofísica, Instituto de Ciencias Biomédicas, Facultad de Medicina, Universidad de Chile, Santiago, Chile
| | - Mario Penna
- Programa de Fisiología y Biofísica, Instituto de Ciencias Biomédicas, Facultad de Medicina, Universidad de Chile, Santiago, Chile
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Daniels O, Fabbro L, Makiela S. The effects of the toxic cyanobacterium Limnothrix (strain AC0243) on Bufo marinus larvae. Toxins (Basel) 2014; 6:1021-35. [PMID: 24662524 PMCID: PMC3968374 DOI: 10.3390/toxins6031021] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2013] [Revised: 02/17/2014] [Accepted: 02/20/2014] [Indexed: 02/07/2023] Open
Abstract
Limnothrix (strain AC0243) is a cyanobacterium, which has only recently been identified as toxin producing. Under laboratory conditions, Bufo marinus larvae were exposed to 100,000 cells mL(-1) of Limnothrix (strain AC0243) live cultures for seven days. Histological examinations were conducted post mortem and revealed damage to the notochord, eyes, brain, liver, kidney, pancreas, gastrointestinal tract, and heart. The histopathological results highlight the toxicological impact of this strain, particularly during developmental stages. Toxicological similarities to β-N-Methylamino-L-alanine are discussed.
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Affiliation(s)
- Olivia Daniels
- School of Medical and Applied Sciences, Central Queensland University, Rockhampton 4701, Australia.
| | - Larelle Fabbro
- School of Medical and Applied Sciences, Central Queensland University, Rockhampton 4701, Australia.
| | - Sandrine Makiela
- School of Medical and Applied Sciences, Central Queensland University, Rockhampton 4701, Australia.
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Hillyard SD, Willumsen NJ. Chemosensory function of amphibian skin: integrating epithelial transport, capillary blood flow and behaviour. Acta Physiol (Oxf) 2011; 202:533-48. [PMID: 21029392 DOI: 10.1111/j.1748-1716.2010.02200.x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Terrestrial anuran amphibians absorb water across specialized regions of skin on the posterioventral region of their bodies. Rapid water absorption is mediated by the insertion of aquaporins into the apical membrane of the outermost cell layer. Water moves out of the epithelium via aquaglyceroporins in the basolateral membrane and into the circulation in conjunction with increased capillary blood flow to the skin and aquaporins in the capillary endothelial cells. These physiological responses are activated by intrinsic stimuli relating to the animals' hydration status and extrinsic stimuli relating to the detection of osmotically available water. The integration of these processes has been studied using behavioural observations in conjunction with neurophysiological recordings and studies of epithelial transport. These studies have identified plasma volume and urinary bladder stores as intrinsic stimuli that activate the formation of angiotensin II (AII) to stimulate water absorption behaviour. The coordinated increase in water permeability and capillary blood flow appears to be mediated primarily by sympathetic stimulation of beta adrenergic receptors, although the neurohypopyseal hormone arginine vasotocin (AVT) may also play a role. Extrinsic stimuli relate primarily to the ionic and osmotic properties of hydration sources. Toads avoid NaCl solutions that have been shown to be harmful in acute exposure, approx. 200-250 mm. The avoidance is partially attenuated by amiloride raising the hypothesis that the mechanism for salt detection by toads resembles that for salt taste in mammals that take in water by mouth. In this model, depolarization of the basolateral membrane of taste cells is coupled to afferent neural stimulation. In toad skin we have identified innervation of skin epithelial cells by branches of spinal nerves and measured neural responses to NaCl solutions that elicit behavioural avoidance. These same concentrations produce depolarization of the basolateral membrane in isolated epithelial preparations. As with salt taste in mammals, the neural responses and depolarization of basolateral membrane potential are partially inhibited by amiloride. In addition, toads are more tolerant of sodium gluconate solution which is consistent with the phenomenon in mammalian taste physiology termed the anion paradox in which sodium salts with larger molecular weight anions produce a reduced intensity of salt taste. Finally, toads also avoid concentrated solutions of a non-electrolyte, mannitol, which differs from NaCl solutions in not affecting transepithelial conductance and requires a longer time to depolarize the basolateral membrane. Osmotic stimuli may mediate sensory processes for longer term detection of conditions with low water potential while ionic stimuli are more important for shorter term analysis of rehydration sources.
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Affiliation(s)
- S D Hillyard
- School of Dental Medicine, University of Nevada, Las Vegas, NV 89106, USA.
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Prutskova NP. Renal filtration and reabsorption of GFP in Rana temporaria: Effect of arginine-vasotocin. J EVOL BIOCHEM PHYS+ 2011. [DOI: 10.1134/s0022093011010087] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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Kaiya H, Koizumi Y, Konno N, Yamamoto K, Uchiyama M, Kangawa K, Miyazato M. Ghrelin Receptor in Two Species of Anuran Amphibian, Bullfrog (Rana catesbeiana), and Japanese Tree Frog (Hyla japonica). Front Endocrinol (Lausanne) 2011; 2:31. [PMID: 22654801 PMCID: PMC3356126 DOI: 10.3389/fendo.2011.00031] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/08/2011] [Accepted: 08/26/2011] [Indexed: 12/28/2022] Open
Abstract
We have identified cDNA encoding a functional growth hormone secretagogue-receptor 1a (GHS-R1a, ghrelin receptor) in two species of anuran amphibian, the bullfrog (Rana catesbeiana), and the Japanese tree frog (Hyla japonica). Deduced receptor protein for bullfrog and Japanese tree frog (tree frog) was comprised of 374- and 371-amino acids, respectively. The two receptors shared 86% identity, and are grouped to the clade of the tetrapod homologs by phylogenetic analysis. In functional analyses, ghrelin and GHS-R1a agonists increased intracellular Ca(2+) concentration in GHS-R1a-transfected-HEK293 cell, but ligand selectivity of ghrelin with Ser(3) and Thr(3) was not observed between the two receptors. Bullfrog GHS-R1a mRNA was mainly expressed in the brain, stomach, and testis. In the brain, the gene expression was detected in the diencephalon and mesencephalon, but not in the pituitary. Tree frog GHS-R1a mRNA was predominantly expressed in the gastrointestinal tract and ovary, but not detected in the pituitary. In bullfrog stomach but not the brain, GHS-R1a mRNA expression increased after 10 days of fasting. For tree frog, GHS-R1a mRNA expression was increased in the brain, stomach and ventral skin by 10 days of fasting, and in the stomach and ventral skin by a dehydration treatment. Intracerebroventricular injection of ghrelin in dehydrated tree frog did not affect water absorption from the ventral skin. These results suggest that ghrelin is involved in energy homeostasis and possibly in osmoregulation in frogs.
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Affiliation(s)
- Hiroyuki Kaiya
- Department of Biochemistry, National Cerebral and Cardiovascular Center Research InstituteSuita, Osaka, Japan
- *Correspondence: Hiroyuki Kaiya, Department of Biochemistry, National Cerebral and Cardiovascular Center Research Institute, 5-7-1 Fujishirodai, Suita, Osaka 565-8565, Japan. e-mail:
| | - Yasushi Koizumi
- Department of Biological Science, Graduated School of Science and Engineering, University of ToyamaToyama, Japan
| | - Norifumi Konno
- Department of Biological Science, Graduated School of Science and Engineering, University of ToyamaToyama, Japan
| | - Kazutoshi Yamamoto
- Laboratory of Integrative Brain Science, Department of Biology, Waseda UniversityTokyo, Japan
| | - Minoru Uchiyama
- Department of Biological Science, Graduated School of Science and Engineering, University of ToyamaToyama, Japan
| | - Kenji Kangawa
- Department of Biochemistry, National Cerebral and Cardiovascular Center Research InstituteSuita, Osaka, Japan
| | - Mikiya Miyazato
- Department of Biochemistry, National Cerebral and Cardiovascular Center Research InstituteSuita, Osaka, Japan
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Johnson WE, Hillyard SD, Propper CR. Plasma and brain angiotensin concentrations associated with water response behavior in the desert anuran, Scaphiopus couchii under natural conditions in the field. Comp Biochem Physiol A Mol Integr Physiol 2010; 157:377-81. [DOI: 10.1016/j.cbpa.2010.08.009] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2010] [Revised: 08/03/2010] [Accepted: 08/04/2010] [Indexed: 11/30/2022]
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Maejima S, Konno N, Matsuda K, Uchiyama M. Central angiotensin II stimulates cutaneous water intake behavior via an angiotensin II type-1 receptor pathway in the Japanese tree frog Hyla japonica. Horm Behav 2010; 58:457-64. [PMID: 20483358 DOI: 10.1016/j.yhbeh.2010.05.007] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/08/2010] [Revised: 05/04/2010] [Accepted: 05/09/2010] [Indexed: 10/19/2022]
Abstract
Angiotensin II (Ang II) stimulates oral water intake by causing thirst in all terrestrial vertebrates except anurans. Anuran amphibians do not drink orally but absorb water osmotically through ventral skin. In this study, we examined the role of Ang II on the regulation of water-absorption behavior in the Japanese tree frog (Hyla japonica). In fully hydrated frogs, intracerebroventricular (ICV) and intralymphatic sac (ILS) injection of Ang II significantly extended the residence time of water in a dose-dependent manner. Ang II-dependent water uptake was inhibited by ICV pretreatment with an angiotensin II type-1 (AT(1)) receptor antagonist but not a type-2 (AT(2)) receptor antagonist. These results suggest that Ang II stimulates water-absorption behavior in the tree frog via an AT(1)-like but not AT(2)-like receptor. We then cloned and characterized cDNA of the tree frog AT(1) receptor from the brain. The tree frog AT(1) receptor cDNA encodes a 361 amino acid residue protein, which is 87% identical to the toad (Bufo marinus) AT(1) receptor and exhibits the functional characteristics of an Ang II receptor. AT(1) receptor mRNAs were found to be present in a number of tissues including brain (especially in the diencephalon), lung, large intestine, kidney and ventral pelvic skin. When tree frogs were exposed to dehydrating conditions, AT(1) receptor mRNA significantly increased in the diencephalon and the rhombencephalon. These data suggest that central Ang II may control water intake behavior via an AT(1) receptor on the diencephalon and rhombencephalon in anuran amphibians and may have implications for water consumption in vertebrates.
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Affiliation(s)
- Sho Maejima
- Department of Life and Environmental Science, Graduate School of Science and Engineering, University of Toyama, Toyama, Japan
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Jared SR, Rao JP, Subramani S. Actions of antidiuretic hormone analogues on intact and nystatin-permeabilized frog skins. Exp Physiol 2009; 94:1174-84. [DOI: 10.1113/expphysiol.2009.048934] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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Vasotocin has the potential to inhibit basolateral Na(+)/K (+)-pump current across isolated skin of tree frog in vitro, via its V(2)-type receptor/cAMP pathway. J Comp Physiol B 2008; 178:957-62. [PMID: 18536923 DOI: 10.1007/s00360-008-0278-4] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2008] [Revised: 05/15/2008] [Accepted: 05/23/2008] [Indexed: 10/22/2022]
Abstract
Adult frog skin transports Na(+) from the apical to the basolateral side across the skin. Antidiuretic hormone (ADH) is involved in the regulation of Na(+) transport in both mammals and amphibians. We investigated the effect of arginine vasotocin (AVT), the ADH of amphibians, on the short-circuit current (SCC) across intact skin and on the basolateral Na(+)/K(+)-pump current across apically nystatin-permeabilized skin of the tree frog, Hyla japonica, in which the V(2)-type ADH receptor is expressed in vitro. In intact skin, 1 pM AVT had no effect on the SCC, but 10 nM AVT was sufficient to stimulate the SCC since 10 nM and 1 microM of AVT increased the SCC 3.2- and 3.4-fold, respectively (P > 0.9). However, in permeabilized skin, AVT (1 microM) decreased the Na(+)/K(+)-pump current to 0.79 times vehicle control. Similarly, 500 microM of 8Br-cAMP increased the SCC 3.2-fold, yet 1 mM of 8Br-cAMP decreased the Na(+)/K(+)-pump current to 0.76 times vehicle control. Arachidonic acid (10(-5) M) tended to decrease the Na(+)/K(+)-pump current. To judge from these in vitro experiments, AVT has the potential to inhibit the basolateral Na(+)/K(+)-pump current via the V(2)-type receptor/cAMP pathway in the skin of the tree frog.
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