Role of Adenosine Signaling on Pentylenetetrazole-Induced Seizures in Zebrafish

Abstract

Adenosine is a well-known endogenous modulator of neuronal excitability with anticonvulsant properties. Thus, the modulation exerted by adenosine might be an effective tool to control seizures. In this study, we investigated the effects of drugs that are able to modulate adenosinergic signaling on pentylenetetrazole (PTZ)-induced seizures in adult zebrafish. The adenosine A 1 receptor antagonist 8-cyclopentyl-1,3-dipropylxanthine (DPCPX) decreased the latency to the onset of the tonic-clonic seizure stage. The adenosine A 1 receptor agonist cyclopentyladenosine (CPA) increased the latency to reach the tonic-clonic seizure stage. Both the adenosine A 2A receptor agonist and antagonist, CGS 21680 and ZM 241385, respectively, did not promote changes in seizure parameters. Pretreatment with the ecto-5¢nucleotidase inhibitor adenosine 5¢-(a,b-methylene) diphosphate (AMPCP) decreased the latency to the onset of the tonic-clonic seizure stage. However, when pretreated with the adenosine deaminase (ADA) inhibitor, erythro-9-(2-hydroxy-3-nonyl)-adenine (EHNA), or with the nucleoside transporter (NT) inhibitors, dipyridamole and S-(4-Nitrobenzyl)-6-thioinosine (NBTI), animals showed longer latency to reach the tonic-clonic seizure status. Finally, our molecular analysis of the c-fos gene expression corroborates these behavioral results. Our findings indicate that the activation of adenosine A 1 receptors is an important mechanism to control the development of seizures in zebrafish. Furthermore, the actions of ecto-5¢-nucleotidase, ADA, and NTs are directly involved in the control of extracellular adenosine levels and have an important role in the development of seizure episodes in zebrafish.

Inhibition of ecto-5′-nucleotidase and adenosine deaminase is able to reverse long-term behavioural effects of early ethanol exposure in zebrafish (Danio rerio)

“…To investigate the effect of adenosine metabolism over behavioural impacts of early ethanol exposure, we used the specific inhibitors of adenosine deaminase, EHNA (erythro-9-(2-hydroxy-3-nonyl)adenine hydrochloride), which could avoid adenosine degradation, and AMPCP (α,β-Methyleneadenosine 5′-diphosphate) an inhibitor of 5′-nucleotidase, which could inhibit adenosine formation by AMP catabolism. The pharmacological treatments (AMPCP at 150 mg/kg or EHNA at 100 mg/kg) of adults were performed by intraperitoneal (ip) injection with the use of a Hamilton microliter syringe in a volume of 10 μL per animal (20 mL/kg), following literature using zebrafish 60 . Prior to the injection, the adult animals were anesthetized in tricaine solution (MS-222; 100 mg/L) 60,61 .…”

“…The pharmacological treatments (AMPCP at 150 mg/kg or EHNA at 100 mg/kg) of adults were performed by intraperitoneal (ip) injection with the use of a Hamilton microliter syringe in a volume of 10 μL per animal (20 mL/kg), following literature using zebrafish 60 . Prior to the injection, the adult animals were anesthetized in tricaine solution (MS-222; 100 mg/L) 60,61 . Behavioural analysis was performed 30 min after drug exposure.…”

Zebrafish Models of Human Disease: Gaining Insight into Human Disease at ZFIN

“…Zebrafish models based on exposure to disease causing conditions AB [ZDB-GENO-960809-7]Chemical treatment: ethanol [ZECO:0000111: CHEBI:16236]Fetal alcohol spectrum disorders (Fernandes et al 2015) [DOID:0050696]WT [ZDB-GENO-030619-2]Increased food availability [ZECO:0000247]Obesity (Montalbano et al 2015) [DOID:9970]WT [ZDB-GENO-030619-2]Bacterial treatment: Mycobacterium marinum [ZECO:0000106: NCBITaxon:1781]Tuberculosis (Sridevi et al 2014) [DOID:399] mitfa w2/w2 ; roy a9/a9 [ZDB-FISH-150901-6638]Viral treatment: influenza virus [ZECO:0000110: NCBITaxon:11309]Influenza (Gabor et al 2014) [DOID:8469]D. Zebrafish models based on disease phenotype similarities TU [ZDB-GENO-990623-3]Chemical treatment: pentetrazol [ZECO:0000111: CHEBI:34910]Epilepsy (Siebel et al 2015) [DOID:1826]WT [ZDB-GENO-030619-2]Chemical treatment: oxidopamine [ZECO:0000111: CHEBI:78741]Parkinson’s disease (Panula et al 2006) [DOID:14330]WT [ZDB-GENO-030619-2]Chemical treatment: N-methyl-4-phenylpyridinium [ZECO:0000111: CHEBI:641] Tg(ins:CFP-NTR) s892Tg [ZDB-FISH-150901-27537]Chemical ablation: insulin secreting cell [ZECO:0000169: ZFA:0009101], chemical treatment: metronidazole [ZECO:0000111: CHEBI:6909]Type 1 diabetes mellitus (Tsuji et al 2014) [DOID:9744]Zebrafish models are defined as ‘Fish’ (genotype, background, and STR) and ‘Experimental Conditions’. They are associated with a disease term from the Disease Ontology (DO).…”

“…To facilitate a better understanding of epilepsy, zebrafish models of epilepsy have been created by administering pentetrazol to induce seizures (Table 1D). Studies that utilize this method have investigated potential therapeutic compounds to alleviate seizure states as well as to understand changes in gene expression due to seizure events (Barbalho et al 2016; Li et al 2015; Siebel et al 2015). PD is a neurodegenerative disease that results from the loss of dopaminergic cells in the brain (Beitz 2014; Pienaar et al 2010).…”

Non-mammalian models in behavioral neuroscience: consequences for biological psychiatry

“…These effects of caffeine on the light/dark test are mimicked by drugs which block the adenosine A 1 receptor, but not A 2 receptors, suggesting a participation of the first, but not the latter, in zebrafish anxiety (Maximino et al, 2011a ). Interestingly, the A 1 receptor has also been shown to protect against the convulsive actions of pentylenotetrazole (Siebel et al, 2015 ), while both receptors have been implicated in the amnestic effects of scopolamine in the inhibitory avoidance test in zebrafish (Bortolotto et al, 2014 ). Treatment with IB-MECA, an agonist at A 3 receptors (which so far have not been described in zebrafish) reduces dark preference in a nitric oxide- and serotonin-dependent manner, while the reduction of bottom-dwelling is dependent on nitric oxide but not serotonin (Maximino et al, 2014b ).…”