Modulation of γ-aminobutyric acid (GABA) receptors and the feeding response by neurosteroids in Hydra vulgaris

Concas, Alessandra; Pierobon, Paola; Mostallino, Maria Cristina; Marino, G.; Minei, Rosario; Biggio, Giovanni

doi:10.1016/s0306-4522(97)00515-0

Cited by 48 publications

(34 citation statements)

References 55 publications

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“…Besides, this finding in the earliest offshoot of the bilaterian stem confirms the assumptions made by Concas et al (1998) and Perovic et al (1999) that GABA-like neurotransmitters occurred early in the animal kingdom.…”

Section: Discussionsupporting

confidence: 88%

Is GABA present in the nervous system of acoel plathelminthes? An electron immunocytochemical study

Bedini

Lanfranchi

Santerini

2001

Italian Journal of Zoology

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Our immunocytochemical investigation positively identified for the first time at the ultrastructural level the presence of GABA-ir neurones and terminals in the nervous system of a plathelminth, the acoel Symsagittifera psammophila. The gold particles are localized on clear vesicles (about 30-60 nm wide) of somata and terminals prevalently distributed in the neuropile area near the statocyst. GABA-ir vesicles are also present at neuromuscular junctions. The significance of this finding in a lower invertebrate is discussed.

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Section: Discussionsupporting

confidence: 88%

Is GABA present in the nervous system of acoel plathelminthes? An electron immunocytochemical study

Bedini

Lanfranchi

Santerini

2001

Italian Journal of Zoology

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“…As predicted from biochemical experiments, GABA A R agonists and positive allosteric modulators mimicked or potentiated these effects of GABA in a dose-dependent manner. The specific GABA B agonist baclofen did not significantly modify duration of the GSH-induced response (Pierobon et al, 1995;Concas et al, 1998).…”

Section: The G-glutamil-cysteinyl-glycine (Gsh) Assaymentioning

confidence: 77%

“…Later studies revealed that Hydra receptor proteins exhibited a complex pharmacological profile (Concas et al, 1998;Pierobon et al, 2004b). The neuroactive steroids allopregnanolone (3a-hydroxy-5a-pregnan-20-one; THP) and tetrahydrodeoxycorticosterone (3a,21-dihydroxy-5a-pregnan-20-one; THDOC) increased [ 3 H]GABA binding.…”

Section: Inhibitory Transmitters and Receptors: Gaba And Glycinementioning

confidence: 99%

Coordinated modulation of cellular signaling through ligand-gated ion channels in Hydra vulgaris (Cnidaria, Hydrozoa)

Pierobon

2012

Int. J. Dev. Biol.

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Cnidarians lack well developed organs, but they have evolved the molecular and cellular components needed to assemble a nervous system. The apparent 'simplicity' of the cnidarian nervous net does not occur at the cellular level, but rather in the organisation of conducting systems. Cnidarian neurons are in fact electrically excitable, show the typical extended morphology and are connected by chemical synapses or gap junctions. They have been regarded as peptidergic, given the wealth of neuropeptides generally distributed along neurites and in cell bodies, supporting the hypothesis of a modulatory role in neurotransmission. However, the presence of clear-cored, as well as dense-cored synaptic vesicles in cnidarian neurons suggests both fast and slow synaptic transmission mechanisms. In fact, biochemical and functional evidence indicates that classical neurotransmitters and their metabolic partners are present in cnidarian tissues, where they are involved in coordinating motility and behavior. We have identified and characterized in Hydra tissues receptors to the inhibitory and excitatory amino acid neurotransmitters, GABA, glycine and NMDA, that are similar to mammalian ionotropic receptors in terms of their biochemical and pharmacological properties. These receptors appear to regulate pacemaker activities and their physiological correlates; in the live animal, they also affect feeding behavior, namely the duration and termination of the response elicited by reduced glutathione, with opposite actions of GABA and glycine or NMDA, respectively. These results suggest that modulation of cellular signaling through ligand-gated-ion channels is an ancient characteristic in the animal kingdom, and that the pharmacological properties of these receptors have been highly conserved during evolution.

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“…Furthermore, no isoallopregnanolone influence has been noted on anesthesia (Gyermek et al 1968), anxiolysis (Bitran et al 1991;Wieland et al 1991;Carboni et al 1996;Rodgers and Johnson 1998), antiepileptic effect (Kokate et al 1994), hyperphagic effect (Chen et al 1996) or stimulation of gastric acid secretion (Watanabe et al 2000). Also, in in vitro experiments no effect of isoallopregnanolone of its own has been detected (Peters et al1988;Lan et al 1991;Lambert et al 1995;Dayanithi and Tapia-Arancibia 1996;Le Foll et al 1997;Calogero et al 1998;Concas et al 1998;Lundgren et al 2003).…”

Section: Introductionmentioning

confidence: 99%

Studies of pharmacokinetic and pharmacodynamic properties of isoallopregnanolone in healthy women

et al. 2008

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Rationale: The pharmacokinetics and behavioral effects of isoallopregnanolone (3β-hydoxy-5α-pregnan-20-one) in women are not known.Objectives: Allopregnanolone (3α-hydoxy-5α-pregnan-20-one) is a well known neurosteriod, acting via the GABA A receptor in the human brain. The naturally occurring progesterone metabolite isoallopregnanolone is the 3β-stereoisomer of allopregnanolone. Prior studies have concluded that isoallopregnanolone has no effect on the GABA A receptor. However, an antagonistic effect of isoallopregnanolone to allopregnanolone on the GABA A receptor has been shown in animal and in vitro studies. The purpose of this study was to evaluate the pharmacokinetics and behavioral effects of isoallopregnanolone in humans.Methods: Six healthy women were given three increasing doses of isoallopregnanolone intravenously in the follicular phase. Repeated blood samples for analyses of isoallopregnanolone and allopregnanolone concentrations were drawn. Saccadic eye movement variables, self rated sedation and mood rating scales were used during the test day.A Likert scale for prospective symptoms was used to measure daily fluctuations during the ongoing menstrual cycle.Results: Exogenously administered isoallopregnanolone produced a dose dependent increase in the serum concentration of isoallopregnanolone. In parallel there was also a rise in the allopregnanolone concentration. There was a decrease in saccade eye movement variables, but no effect was found on self-rated sedation or mood and no changes were seen in prospective symptoms during the menstrual cycle.Conclusions: After administration of isoallopregnanolone at a cumulative dose of 0.20 mg/kg, no adverse effects were observed. There is a metabolism of isoallopregnanolone to allopregnanolone, most likely explaining the effects on the saccadic eye movements.3

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Modulation of γ-aminobutyric acid (GABA) receptors and the feeding response by neurosteroids in Hydra vulgaris

Cited by 48 publications

References 55 publications

Is GABA present in the nervous system of acoel plathelminthes? An electron immunocytochemical study

Is GABA present in the nervous system of acoel plathelminthes? An electron immunocytochemical study

Coordinated modulation of cellular signaling through ligand-gated ion channels in Hydra vulgaris (Cnidaria, Hydrozoa)

Studies of pharmacokinetic and pharmacodynamic properties of isoallopregnanolone in healthy women

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