The Neurokinin 1 Receptor Antagonist, Ezlopitant, Reduces Appetitive Responding for Sucrose and Ethanol

Abstract Background: The current obesity epidemic is thought to be partly driven by over-consumption of sugar-sweetened diets and soft drinks. Loss-of-control over eating and addiction to drugs of abuse share overlapping brain mechanisms including changes in motivational drive, such that stimuli that are often no longer ‘liked’ are still intensely ‘wanted’ [7,8]. The neurokinin 1 (NK1) receptor system has been implicated in both learned appetitive behaviors and addiction to alcohol and opioids; however, its role in natural reward seeking remains unknown. Methodology/Principal Findings: We sought to determine whether the NK1-receptor system plays a role in the reinforcing properties of sucrose using a novel selective and clinically safe NK1-receptor antagonist, ezlopitant (CJ-11,974), in three animal models of sucrose consumption and seeking. Furthermore, we compared the effect of ezlopitant on ethanol consumption and seeking in rodents. The NK1-receptor antagonist, ezlopitant decreased appetitive responding for sucrose more potently than for ethanol using an operant self-administration protocol without affecting general locomotor activity. To further evaluate the selectivity of the NK1-receptor antagonist in decreasing consumption of sweetened solutions, we compared the effects of ezlopitant on water, saccharin-, and sodium chloride (NaCl) solution consumption. Ezlopitant decreased intake of saccharin but had no effect on water or salty solution consumption. Conclusions/Significance: The present study indicates that the NK1-receptor may be a part of a common pathway regulating the self-administration, motivational and reinforcing aspects of sweetened solutions, regardless of caloric value, and those of substances of abuse. Additionally, these results indicate that the NK1-receptor system may serve as a therapeutic target for obesity induced by over-consumption of natural reinforcers

Spatial Learning and Action Planning in a Prefrontal Cortical Network Model

The interplay between hippocampus and prefrontal cortex (PFC) is fundamental to spatial cognition. Complementing hippocampal place coding, prefrontal representations provide more abstract and hierarchically organized memories suitable for decision making. We model a prefrontal network mediating distributed information processing for spatial learning and action planning. Specific connectivity and synaptic adaptation principles shape the recurrent dynamics of the network arranged in cortical minicolumns. We show how the PFC columnar organization is suitable for learning sparse topological-metrical representations from redundant hippocampal inputs. The recurrent nature of the network supports multilevel spatial processing, allowing structural features of the environment to be encoded. An activation diffusion mechanism spreads the neural activity through the column population leading to trajectory planning. The model provides a functional framework for interpreting the activity of PFC neurons recorded during navigation tasks. We illustrate the link from single unit activity to behavioral responses. The results suggest plausible neural mechanisms subserving the cognitive “insight” capability originally attributed to rodents by Tolman & Honzik. Our time course analysis of neural responses shows how the interaction between hippocampus and PFC can yield the encoding of manifold information pertinent to spatial planning, including prospective coding and distance-to-goal correlates

Associação singular de síndrome de Kallmann e cisto aracnóide da fossa média: relato de caso Singular association of Kallmann's syndrome and arachnoid cyst of middle fossa: case report

O hipogonadismo hipogonadotrófico pode resultar de diferentes anomalias do sistema nervoso central, apresentando sinais clínicos que dependem da idade de aparecimento, bem como do grau de deficiência gonadotrófica e de sua associação com outras deficiências hipofisárias. Relatamos o caso de um rapaz de 18 anos com atraso puberal, retardo de crescimento estatural a partir de 10 anos e história de dificuldade de aprendizado escolar. Ao exame apresentava discreto aspecto eunucóide, 162 cm de altura (z score = -2,17), estadiamento puberal GII, PII, testículos de 4 cm³. A avaliação complementar demonstrou níveis pré-puberais de testosterona, megateste com resposta normal, exceto ao teste de estímulo com GnRH agudo e prolongado. CT de crânio mostrou cisto aracnóide da fossa média esquerda com extensão supra-selar. Foi feito o diagnóstico de hipogonadismo hipogonadotrófico provavelmente secundário à compressão pelo cisto aracnóide e por isso, optou-se por derivação cisto-peritoneal. Após a cirurgia não houve retomada do desenvolvimento puberal, sendo então verificada anosmia bilateral e, portanto, diagnosticada Síndrome de Kallmann, que foi confirmada pelos achados da RNM, embora os resultados hormonais não sejam totalmente compatíveis com a referida síndrome. Não encontramos na literatura descrição da associação entre Síndrome de Kallmnann e cisto aracnóide e acreditamos que neste caso os resultados da avaliação hormonal possam ser devidos a tal associação que provocou adicionalmente uma disfunção hipofisária.<br>Hypogonadotrophic hypogonadism can result from different abnormalities in the central nervous system. The clinical picture depends upon the time of onset the deficiency, the magnitude of the gonadotropins deficiency and whether there are other pituitary hormone deficiencies as well. We report on a 18-year-old boy, who was investigated because of pubertal and growth delay. He also had learning disabilities. On physical examination he exhibited mild eunuchoid aspect, 162 cm height (z score = -2,17), pubertal development on stage G II, P II, and 4 cm5 testis. Laboratory investigation revealed pre-pubertal levels of testosterone and normal results of the combined test of anterior pituitary function, except for in GnRH acute and prolonged test. Brain CT showed an arachnoid cyst on left middle fossa with expansion to suprasellar cisterna. He was diagnosed as having hypogonadotrophic hypogonadism secondary to compression by the cyst, and a cyst-peritoneal derivation was performed. After surgery there was no improvement of the pubertal state and bilateral anosmia was discovered, so Kallmann's syndrome was then diagnosed and was confirmed by MRI, even though the hormonal results are not totally matched with the refered syndrome. We did not find in the literature any description of the association between Kallmann's syndrome and arachnoid cyst and we believe that in this case the results of the hormonal measurement may be due to such association that provoked an additional hypophysis dysfunction