The effects of BRL-50481 on ovalbumin-induced asthmatic lung inflammation exacerbated by co-exposure to Asian sand dust in the murine model.

Asian sand dust (ASD), which mainly originates in China and Mongolia in the spring and blows into Korea, can exacerbate respiratory and immunological diseases. This study aims to observe effects of co-exposure to ASD on ovalbumin (OVA)-induced asthmatic lung inflammation and of treatment with a phosphodiesterase 7 (PDE7) inhibitor in a mouse model. The challenge with OVA increased airway hyperresponsiveness (AHR) and inflammatory cell infiltration into the lung tissue. Interleukin (IL)-13, tumor necrosis factor-alpha, monocyte-protein-1, mucin, and antigen-specific IgE and IgG1 production increased in mouse serum. The co-exposure of ASD significantly exacerbated these effects in this asthma model. Notably, the administration of a PDE7 inhibitor, BRL-50481 (BRL), significantly reduced AHR, infiltration of inflammatory cells into the lungs, and the levels of type 2 T helper cell-related cytokines, antigen-specific immunoglobulins, and mucin. Thus, the administration of BRL ameliorated OVA-induced allergic asthmatic responses exacerbated by co-exposure to ASD. This study suggests that PDE7 inhibition can be a therapeutic strategy for inflammatory lung diseases and asthma via the regulation of T lymphocytes and reduction of IL-13, and, consequently, mucin production.

Estimation of the lipophilicity of purine-2,6-dione-based TRPA1 antagonists and PDE4/7 inhibitors with analgesic activity.

Lipophilicity is one of the principal QSAR parameters which influences among others the pharmacodynamics and pharmacokinetic properties of a drug candidates. In this paper, the lipophilicity of 14 amide derivatives of 1,3-dimethyl-2,6-dioxopurin-7-yl-alkylcarboxylic acids as multifunctional TRPA1 channel antagonists and phosphodiesterase 4/7 inhibitors with analgesic activity were investigated, using reversed-phase thin-layer chromatography method. It was observed that the retention behavior of the analyzed compounds was dependent on their structural features i.e. an aliphatic linker length, a kind of substituent at 8 position of purine-2,6-dione scaffold as well as on a substitution in a phenyl group. The experimental parameters (RM0) were compared with computationally calculated partition coefficient values by Principal Component Analysis (PCA). To verify the influence of lipophilic parameter of the investigated compounds on their biological activity the Kruskal-Wallis test was performed. The lowest lipophilicity was observed for the compounds with weak PDE4/7 inhibitory potency. The differences between the lipophilicity of potent inhibitors and inactive compounds were statistically significant. It was found that the presence of more lipophilic propoxy- or butoxy- substituents as well as the elongation of the aliphatic chain to propylene one between the purine-2,6-dione core and amide group were preferable for desired multifunctional activity.

Phosphodiesterase 7(PDE7): A unique drug target for central nervous system diseases.

Phosphodiesterase 7 (PDE7), one of the 11 phosphodiesterase (PDE) families, specifically hydrolyzes cyclic 3', 5'-adenosine monophosphate (cAMP). PDE7 is involved in many important functional processes in physiology and pathology by regulating intracellular cAMP signaling. Studies have demonstrated that PDE7 is widely expressed in the central nervous system (CNS) and potentially related to pathogenesis of many CNS diseases. Here, we summarized the classification and distribution of PDE7 in the brain and its functional roles in the mediation of CNS diseases such as Parkinson's disease (PD), Alzheimer's disease (AD), multiple sclerosis (MS), and schizophrenia. It is expected that the findings collected here will not only lead to a better understanding of the mechanisms by which PDE7 mediates CNS function and diseases, but also aid in the development of novel drugs targeting PDE7 for treatment of CNS diseases.

Improved Controlled Release and Brain Penetration of the Small Molecule S14 Using PLGA Nanoparticles.

Phosphodiesterase 7 (PDE7) is an enzyme responsible for the degradation of cyclic adenosine monophosphate (cAMP), an important cellular messenger. PDE7's role in neurotransmission, expression profile in the brain and the druggability of other phosphodiesterases have motivated the search for potent inhibitors to treat neurodegenerative and inflammatory diseases. Different heterocyclic compounds have been described over the years; among them, phenyl-2-thioxo-(1H)-quinazolin-4-one, called S14, has shown very promising results in different in vitro and in vivo studies. Recently, polymeric nanoparticles have been used as new formulations to target specific organs and produce controlled release of certain drugs. In this work, we describe poly(lactic-co-glycolic acid) (PLGA)-based polymeric nanoparticles loaded with S14. Their preparation, optimization, characterization and in vivo drug release profile are here presented as an effort to improve pharmacokinetic properties of this interesting PDE7 inhibitor.

New imidazopyridines with phosphodiesterase 4 and 7 inhibitory activity and their efficacy in animal models of inflammatory and autoimmune diseases.

Herein, we describe the rapid synthesis of a focused library of trisubstituted imidazo[4,5-b]pyridines and imidazo[4,5-c]pyridines from 2,4-dichloro-3-nitropyridine using the combination of solution-phase/solid-phase chemistry as new potential anti-inflammatory agents in the treatment of autoimmune diseases. Structure-activity relationship studies, followed by the structure optimization, provided hit compounds (17 and 28) which inhibited phosphodiesterase 4 (PDE4) with IC50 values comparable to rolipram and displayed different inhibitory potency against phosphodiesterase 7 (PDE7). Among them, compound 17 showed a beneficial effect in all the studied animal models of inflammatory and autoimmune diseases (concanavalin A-induced hepatitis, lipopolysaccharide-induced endotoxemia, collagen-induced arthritis, and MOG35-55-induced encephalomyelitis). In addition, compound 17 showed a favorable pharmacokinetic profile after intraperitoneal administration; it was characterized by a fast absorption from the peritoneal cavity and a relatively long terminal half-life in rats. It was found to penetrate brain barrier in mice. The performed experiments sheds light on the impact of PDE7A inhibition for the efficacy of PDE4 inhibitors in these disease conditions.

Pharmacological inhibition of phosphodiesterase 7 enhances consolidation processes of spatial memory.

Augmentation of cAMP signaling through inhibition of phosphodiesterases (PDE) is known to enhance plasticity and memory. Inhibition of PDE4 enhances consolidation into memory, but less is known about the role of other cAMP specific PDEs. Here, we tested the effects of oral treatment with a selective inhibitor of PDE7 of nanomolar potency on spatial and contextual memory. In an object location task, doses of 0.3-3 mg/kg administered 3 h after training dose-dependently attenuated time-dependent forgetting in rats. Significant enhancement of memory occurred at a dose of 3 mg/kg with corresponding brain levels consistent with PDE7 inhibition. The same dose given prior to training augmented contextual fear conditioning. In mice, daily dosing before training enhanced spatial memory in two different incremental learning paradigms in the Barnes Maze. Drug treated mice made significantly less errors locating the escape in a probe-test 24 h after the end of training, and they exhibited hippocampal-dependent spatial search strategies more frequently than controls, which tended to show serial sampling of escape locations. Acquisition and short-term memory, in contrast, were unaffected. Our data provide evidence for a role of PDE7 in the consolidation of hippocampal-dependent memory. We suggest that targeting PDE7 for memory enhancement may provide an alternative to PDE4 inhibitors, which tend to have undesirable gastrointestinal side-effects.

Novel anilide and benzylamide derivatives of arylpiperazinylalkanoic acids as 5-HT1A/5-HT7 receptor antagonists and phosphodiesterase 4/7 inhibitors with procognitive and antidepressant activity.

A library of novel anilide and benzylamide derivatives of ω-(4-(2-methoxyphenyl)piperazin-1-yl)alkanoic acids as combined 5-HT1A/5-HT7 receptor ligands and phosphodiesterase PDE4B/PDE7A inhibitors was designed using a structure-based drug design approach. The in vitro studies of 33 newly synthesized compounds (7-39) allowed us to identify 22 as the most promising multifunctional 5-HT1A/5-HT7 receptor antagonist (5-HT1AKi = 8 nM, Kb = 0.04 nM; 5-HT7Ki = 451 nM, Kb = 460 nM) with PDE4B/PDE7A inhibitory activity (PDE4B IC50 = 80.4 µM; PDE7A IC50 = 151.3 µM). Compound 22 exerted a very good ability to passively penetrate through biological membranes and a high metabolic stability in vitro. Moreover, the pharmacological evaluation of 22 showed its procognitive and antidepressant properties in rat behavioral tests. Compound 22 at a dose of 3 mg/kg (i.p.) significantly reversed MK-801-induced episodic memory deficits in the novel object recognition test, while at a dose of 10 mg/kg (i.p.) reduced the immobility time of animals (by about 34%) in the forced swimming test. The antidepressant-like effect produced by compound 22 was stronger than that of escitalopram used as a reference drug. This study opens a new perspective in the search for efficacious drugs for the treatment of cognitive and depressive disorders.

Synthesis, biological screening, and molecular docking of quinazolinone and quinazolinethione as phosphodiesterase 7 inhibitors.

N-Substituted isatoic anhydrides were used as starting materials for the synthesis of compounds 5-16 through alkali hydrolysis, Schiff base reactions, and oxidation. Compounds 18-23 were obtained by thionation of their oxo isosteres using Lawesson's reagent. Cyclocondesation of anthranilic acid with thiourea afforded compounds 25-27, which were S-alkylated to afford compounds 28-30, which were thionated using Lawesson's reagent to afford 31-33. The compounds were tested for their in vitro inhibitory activity against the phosphodiesterase 7A (PDE7A) enzyme compared with the selective PDE7 inhibitor BRL50481. All the compounds showed the inhibitory activity on the enzyme at micromolar levels. Compounds 9 and 25 showed the highest inhibitory activity on the enzyme: IC50 = 0.096 and 0.074 µM, respectively, comparable to BRL50481 (IC50 = 0.072 µM). The binding mode and binding affinity of the target compounds at the enzyme PDE7A-binding site were studied through molecular docking. Compounds 9 and 25 showed good recognition at the enzyme-binding site and were capable of binding in an inhibitory mode similar to the reference compound BRL50481, forming the necessary interactions with the key amino acids. Docking studies and enzyme assay were in agreement.

Effects of Specific Inhibitor of Phosphodiesterase 7 at the Late Stage of Long-Term Potentiation in Murine Hippocampal Slices.

Second messengers cAMP and cGMP play an important role in synaptic plasticity and memory consolidation. The inhibitors of phosphodiesterases, enzymes hydrolyzing these cyclic nucleotides, are actively studied as potential drugs for the treatment of various cognitive disorders and depression. We studied the effects of a new inhibitor of phosphodiesterase 7 AGF2.20 on the formation of long-term potentiation in hippocampal slices. Administration of AGF2.20 (10 nM) in 90 min after weak tetanization prevented a decrease in the amplitude of excitatory post-synaptic potentials and stabilized long-term potentiation. These data attest to the involvement of phosphodiesterase 7 in the development of synaptic plasticity in the hippocampus. The inhibitor AGF2.20 is considered for the further analysis as a promising substance for the treatment of cognitive impairments.

Synthesis, Anti-inflammatory Activity and Docking Studies of Some Newer 1,3-Thiazolidine-2,4-dione Derivatives as Dual Inhibitors of PDE4 and PDE7.

BACKGROUND: Phosphodiesterase 4 (PDE4) and phosphodiesterase 7 (PDE7), PDE superfamily members, increase inflammatory processes in immunomodulatory as well as pro-inflammatory cells via breakdown of cyclic adenosine monophosphate. Dual inhibitors of PDE4 and PDE7 are a novel class of drug candidates which can regulate pro-inflammatory as well as T-cell function and can be particularly advantageous in the treatment of a wide-ranging disorders associated with the immune system as well as inflammatory diseases with fewer unwanted adverse effects. OBJECTIVE: The current research work was planned to design and synthesize some newer substituted 1,3- thiazolidine-2,4-dione derivatives as dual inhibitors of PDE4 and PDE7 followed by evaluation of their anti-inflammatory activity and in silico docking studies. METHODS: A new series of substituted 1,3-thiazolidine-2,4-dione derivatives was synthesized followed by evaluation of their anti-inflammatory activity in animal models. In silico docking studies were performed for the evaluation of the binding pattern of synthesized derivatives in the binding site of both PDE4 and PDE7 proteins. RESULTS: Amongst the newly synthesized derivatives, compounds 5 and 12 showed higher antiinflammatory activity in the animal model. The results of in vivo animal studies were found to be in concordance with the results of molecular docking studies. CONCLUSION: These newly synthesized derivatives can act as the lead molecules for the design of safe and therapeutically effective agents for various inflammatory diseases acting via inhibition of both PDE4 and PDE7.

Novel amide derivatives of 1,3-dimethyl-2,6-dioxopurin-7-yl-alkylcarboxylic acids as multifunctional TRPA1 antagonists and PDE4/7 inhibitors: A new approach for the treatment of pain.

A series of novel amide derivatives of 1,3-dimethyl-2,6-dioxopurin-7-yl-alkylcarboxylic acids designed using a structure-based computational approach was synthesized and assayed to evaluate their ability to block human TRPA1 channel and inhibit PDE4B/7A activity. We identified compounds 16 and 27 which showed higher potency against TRPA1 compared to HC-030031. In turn, compound 36 was the most promising multifunctional TRPA1 antagonist and PDE4B/7A dual inhibitor with IC50 values in the range of that of the reference rolipram and BRL-50481, respectively. Compound 36 as a combined TRPA1/PDE4B/PDE7A ligand was characterized by a distinct binding mode in comparison to 16 and 27, in the given protein targets. The inhibition of both cAMP-specific PDE isoenzymes resulted in a strong anti-TNF-α effect of 36in vivo. Moreover, the potent anti-inflammatory and analgesic efficacy of 36 was observed in animal models of pain and inflammation (formalin test in mice and carrageenan-induced paw edema in rats). This compound also displayed significant antiallodynic properties in the early phase of chemotherapy-induced peripheral neuropathy in mice. In turn, the pure TRPA1 antagonists 16 and 27 revealed a statistically significant antiallodynic effect in the formalin test and in the von Frey test performed in both phases of oxaliplatin-induced allodynia. Antiallodynic activity of the test compounds 16, 27 and 36 was observed at a dose range comparable to that of the reference drug - pregabalin. In conclusion, the proposed approach of pain treatment based on the concomitant blocking of TRPA1 channel and PDE4B/7A inhibitory activity appears to be interesting research direction for the future search for novel analgesics.

Design and synthesis of novel annulated thienopyrimidines as phosphodiesterase 5 (PDE5) inhibitors.

Novel cycloalkene-fused thienopyrimidine analogues with enhanced phosphodiesterase 5 (PDE5) inhibitory properties are presented. The structure of the reported scaffold was modulated through variation of the terminal cycloalkene ring size, as well as by varying the substituents at position 4 through the attachment of different groups including aniline, benzylamine, cyclohexylethylamine, methyl/acetyl/aryl piperazines, and aryl hydrazones. Compound 15Y with a benzylamine substituent and cycloheptene as terminal ring showed the highest PDE5 inhibitory activity with an IC50 value as low as 190 nM and with good selectivity versus PDE7 and PDE9.

Multiple cAMP Phosphodiesterases Act Together to Prevent Premature Oocyte Meiosis and Ovulation.

Luteinizing hormone (LH) acts on the granulosa cells that surround the oocyte in mammalian preovulatory follicles to cause meiotic resumption and ovulation. Both of these responses are mediated primarily by an increase in cyclic adenosine monophosphate (cAMP) in the granulosa cells, and the activity of cAMP phosphodiesterases (PDEs), including PDE4, contributes to preventing premature responses. However, two other cAMP-specific PDEs, PDE7 and PDE8, are also expressed at high levels in the granulosa cells, raising the question of whether these PDEs also contribute to preventing uncontrolled activation of meiotic resumption and ovulation. With the use of selective inhibitors, we show that inhibition of PDE7 or PDE8 alone has no effect on the cAMP content of follicles, and inhibition of PDE4 alone has only a small and variable effect. In contrast, a mixture of the three inhibitors elevates cAMP to a level comparable with that seen with LH. Correspondingly, inhibition of PDE7 or PDE8 alone has no effect on meiotic resumption or ovulation, and inhibition of PDE4 alone has only a partial and slow effect. However, the fraction of oocytes resuming meiosis and undergoing ovulation is increased when PDE4, PDE7, and PDE8 are simultaneously inhibited. PDE4, PDE7, and PDE8 also function together to suppress the premature synthesis of progesterone and progesterone receptors, which are required for ovulation. Our results indicate that three cAMP PDEs act in concert to suppress premature responses in preovulatory follicles.

Novel butanehydrazide derivatives of purine-2,6-dione as dual PDE4/7 inhibitors with potential anti-inflammatory activity: Design, synthesis and biological evaluation.

A novel butanehydrazide derivatives of purine-2,6-dione designed using a ligand-based approach were synthesized and their in vitro activity against both PDE4B and PDE7A isoenzymes was assessed. The 7,8-disubstituted purine-2,6-dione derivatives 31, 34, 37, and 40 appeared to be the most potent PDE4/7 inhibitors with IC50 values in the range of that of the reference rolipram and BRL-50481, respectively. Moreover, docking studies explained the importance of N-(2,3,4-trihydroxybenzylidene)butanehydrazide substituent in position 7 of purine-2,6-dione core for dual PDE4/7 inhibitory properties. The inhibition of both the cAMP-specific PDE isoenzymes resulted in a strong anti-TNF-α effect. Compounds 31, 34, and 37 in the in vivo study in rats with LPS-induced endotoxemia decreased the maximum concentration of this proinflammatory cytokine by 53, 84 and 88%, respectively.

Identification and characterization of a potent and biologically-active PDE4/7 inhibitor via fission yeast-based assays.

We previously constructed a collection of fission yeast strains that express various mammalian cyclic nucleotide phosphodiesterases (PDEs) and developed a cell-based high throughput screen (HTS) for small molecule PDE inhibitors. Here we describe a compound, BC54, that is a selective inhibitor of enzymes from the cAMP-specific PDE4 and PDE7 families. Consistent with the biological effect of other PDE4 and PDE7 inhibitors, BC54 displays potent anti-inflammatory properties and is superior to a combination of rolipram (a PDE4 inhibitor) and BRL50481 (a PDE7A inhibitor) for inducing apoptosis in chronic lymphocytic leukemia (CLL) cells. We further exploited PKA-regulated growth phenotypes in fission yeast to isolate two mutant alleles of the human PDE4B2 gene that encode enzymes possessing single amino acid changes that confer partial resistance to BC54. We confirm this resistance to both BC54 and rolipram via yeast-based assays and, for PDE4B2T407A, in vitro enzyme assays. Thus, we are able to use this system for both chemical screens to identify biologically-active PDE inhibitors and molecular genetic studies to characterize the interaction of these molecules with their target enzymes. Based on its potency, selectivity, and effectiveness in cell culture, BC54 should be a useful tool to study biological processes regulated by PDE4 and PDE7 enzymes.

Promoting in vivo remyelination with small molecules: a neuroreparative pharmacological treatment for Multiple Sclerosis.

Multiple Sclerosis (MS) is a neurodegenerative disease where immune-driven demyelination occurs with inefficient remyelination, but therapies are limited, especially those to enhance repair. Here, we show that the dual phosphodiesterase (PDE)7- glycogen synthase kinase (GSK)3 inhibitor, VP3.15, a heterocyclic small molecule with good pharmacokinetic properties and safety profile, improves in vivo remyelination in mouse and increases both adult mouse and adult human oligodendrocyte progenitor cell (OPC) differentiation, in addition to its immune regulatory action. The dual inhibition is synergistic, as increasing intracellular levels of cAMP by cyclic nucleotide PDE inhibition both suppresses the immune response and increases remyelination, and in addition, inhibition of GSK3 limits experimental autoimmune encephalomyelitis in mice. This combination of an advantageous effect on the immune response and an enhancement of repair, plus demonstration of its activity on adult human OPCs, leads us to propose dual PDE7-GSK3 inhibition, and specifically VP3.15, as a neuroprotective and neuroreparative disease-modifying treatment for MS.

PDE7-Selective and Dual Inhibitors: Advances in Chemical and Biological Research.

Phosphodiesterase 7 (PDE7) is an intracellular enzyme that specifically hydrolyzes the second messenger, cyclic-3',5'-adenosine monophosphate (cAMP), into inactive noncyclic nucleotide, 5'-AMP. To date, many structurally diverse compounds with PDE7 inhibitory properties have been described, including selective PDE7 inhibitors, dual PDE4/PDE7, PDE7/PDE8, and PDE7/GSK-3 inhibitors, and non-selective PDE inhibitors with high affinity for PDE7. Inhibitors of PDE7 have provided beneficial effects in animal models of inflammatory and neurological disorders, including Alzheimer's disease, Parkinson's disease, multiple sclerosis, and many others. This review is a comprehensive summary of the current state-of-the-art in the field of design and synthesis of PDE7 inhibitors, their physicochemical properties, biological evaluation, and structure-activity relationships as well as it highlights the updated evidence for a potential therapeutic utility of these compounds. Moreover, new approaches to obtain more effective and safer PDE7 inhibitors than those available now are presented.

Phosphodiesterase7 Inhibition Activates Adult Neurogenesis in Hippocampus and Subventricular Zone In Vitro and In Vivo.

The phosphodiesterase 7 (PDE7) enzyme is one of the enzymes responsible for controlling intracellular levels of cyclic adenosine 3',5'-monophosphate in the immune and central nervous system. We have previously shown that inhibitors of this enzyme are potent neuroprotective and anti-inflammatory agents. In addition, we also demonstrated that PDE7 inhibition induces endogenous neuroregenerative processes toward a dopaminergic phenotype. Here, we show that PDE7 inhibition controls stem cell expansion in the subgranular zone of the dentate gyrus of the hippocampus (SGZ) and the subventricular zone (SVZ) in the adult rat brain. Neurospheres cultures obtained from SGZ and SVZ of adult rats treated with PDE7 inhibitors presented an increased proliferation and neuronal differentiation compared to control cultures. PDE7 inhibitors treatment of neurospheres cultures also resulted in an increase of the levels of phosphorylated cAMP response element binding protein, suggesting that their effects were indeed mediated through the activation of the cAMP/PKA signaling pathway. In addition, adult rats orally treated with S14, a specific inhibitor of PDE7, presented elevated numbers of proliferating progenitor cells, and migrating precursors in the SGZ and the SVZ. Moreover, long-term treatment with this PDE7 inhibitor shows a significant increase in newly generated neurons in the olfactory bulb and the hippocampus. Also a better performance in memory tests was observed in S14 treated rats, suggesting a functional relevance for the S14-induced increase in SGZ neurogenesis. Taken together, our results indicate for the first time that inhibition of PDE7 directly regulates proliferation, migration and differentiation of neural stem cells, improving spatial learning and memory tasks. Stem Cells 2017;35:458-472.

A preliminary investigation of phoshodiesterase 7 inhibitor VP3.15 as therapeutic agent for the treatment of experimental autoimmune encephalomyelitis mice.

cAMP plays a significant role in signal transduction pathways controlling multiple cellular processes such as inflammation and immune regulation. cAMP levels are regulated by a family of phosphodiesterases (PDEs). We have studied the effects of a novel PDE7 inhibitor (PDE7i) treatment on mice with experimental autoimmune encephalomyelitis (EAE) a model of multiple sclerosis (MS) and compared it with another PDE7i. EAE was induced by immunizing C57BL/6J mice with myelin oligodendrocyte glycoprotein (MOG35-55) peptide. Mice were treated daily either from disease onset or from disease peak with each PDE7i and with fingolimod (used in therapy for MS patients) and disease evolution was followed by clinical symptoms. We examined neuropathology of spinal cord, ex vivo lymphocyte proliferation by [3H]-thymidine incorporation, TNFα by ELISA and cAMP-PDE mRNAs expression by in situ hybridization histochemistry (ISHH) in spinal cord of EAE mice treated with both PDE7 inhibitors. Treatment of EAE mice with the novel PDE7i, VP3.15 showed more efficacy in reducing clinical signs at 10mgkg-1 than the other PDE7i, BRL50481 and similar to fingolimod. VP3.15 acts on peripheral lymphocytes inhibiting their proliferation and TNFα secretion in a dose-dependent manner. PDE7i treatment alters the levels of PDE4B and PDE7 mRNA expression in EAE mice spinal cord. Given the interest in the development of new drugs for MS, including PDE7i as anti-inflammatory drugs, it is important to study the role played by PDE7 in neurodegenerative diseases with inflammatory component to better understand the beneficial and detrimental effects of a future therapy.

Phosphodiesterase-7 inhibition affects accumbal and hypothalamic thyrotropin-releasing hormone expression, feeding and anxiety behavior of rats.

Thyrotropin-releasing hormone (TRH) has anorexigenic and anxiolytic functions when injected intraventricularly. Nucleus accumbens (NAcc) is a possible brain region involved, since it expresses proTRH. TRH from hypothalamic paraventricular nucleus (PVN) has a food intake-regulating role. TRHergic pathways of NAcc and PVN are implicated in anxiety and feeding. Both behaviors depend on cAMP and phosphorylated-cAMP response element binding protein (pCREB) intracellular levels. Intracellular levels of cAMP are controlled by the degrading activity of phosphodiesterases (PDEs). Since TRH transcription is activated by pCREB, a specific inhibitor of PDE7B may regulate TRH-induced effects on anxiety and feeding. We evaluated the effectiveness of an intra-accumbal and intraperitoneal (i.p.) administration of a PDE7 inhibitor (BRL-50481) on rats' anxiety-like behavior and food intake; also on TRH mRNA and protein expression in NAcc and PVN to define its mediating role on the PDE7 inhibitor-induced behavioral changes. Accumbal injection of 4µg/0.3µL of PDE7 inhibitor decreased rats' anxiety. The i.p. injection of 0.2mg/kg of the inhibitor was able to increase the PVN TRH mRNA expression and to decrease feeding but did not change animals' anxiety levels; in contrast, 2mg/kg b.w inhibitor enhanced accumbal TRH mRNA, induced anxiolysis with no change in food intake. PDE7 inhibitor induced anxiolytic and anorexigenic like behavior depending on the dose used. Results supported hypothalamic TRH mediated feeding-reduction effects, and accumbal TRH mediation of inhibitor-induced anxiolysis. Thus, an i.p dose of this inhibitor might be reducing anxiety with no change in feeding, which could be useful for obese patients.