A Deep Mesencephalic Nucleus Circuit Regulates Licking Behavior / 神经科学通报·英文版

Licking behavior is important for water intake. The deep mesencephalic nucleus (DpMe) has been implicated in instinctive behaviors. However, whether the DpMe is involved in licking behavior and the precise neural circuit behind this behavior remains unknown. Here, we found that the activity of the DpMe decreased during water intake. Inhibition of vesicular glutamate transporter 2-positive (VGLUT2+) neurons in the DpMe resulted in increased water intake. Somatostatin-expressing (SST+), but not protein kinase C-δ-expressing (PKC-δ+), GABAergic neurons in the central amygdala (CeA) preferentially innervated DpMe VGLUT2+ neurons. The SST+ neurons in the CeA projecting to the DpMe were activated at the onset of licking behavior. Activation of these CeA SST+ GABAergic neurons, but not PKC-δ+ GABAergic neurons, projecting to the DpMe was sufficient to induce licking behavior and promote water intake. These findings redefine the roles of the DpMe and reveal a novel CeASST-DpMeVGLUT2 circuit that regulates licking behavior and promotes water intake.

Effects of Intraperitoneal N-methyl-D-aspartate (NMDA) Administration on Nociceptive/Repetitive Behaviors in Juvenile Mice

Dysregulation of excitatory neurotransmission has been implicated in the pathogenesis of neuropsychiatric disorders. Pharmacological inhibition of N-methyl-D-aspartate (NMDA) receptors is widely used to model neurobehavioral pathologies and underlying mechanisms. There is ample evidence that overstimulation of NMDA-dependent neurotransmission may induce neurobehavioral abnormalities, such as repetitive behaviors and hypersensitization to nociception and cognitive disruption, pharmacological modeling using NMDA has been limited due to the induction of neurotoxicity and blood brain barrier breakdown, especially in young animals. In this study, we examined the effects of intraperitoneal NMDA-administration on nociceptive and repetitive behaviors in ICR mice. Intraperitoneal injection of NMDA induced repetitive grooming and tail biting/licking behaviors in a dose- and age-dependent manner. Nociceptive and repetitive behaviors were more prominent in juvenile mice than adult mice. We did not observe extensive blood brain barrier breakdown or neuronal cell death after peritoneal injection of NMDA, indicating limited neurotoxic effects despite a significant increase in NMDA concentration in the cerebrospinal fluid. These findings suggest that the observed behavioral changes were not mediated by general NMDA toxicity. In the hot plate test, we found that the latency of paw licking and jumping decreased in the NMDA-exposed mice especially in the 75 mg/kg group, suggesting increased nociceptive sensitivity in NMDA-treated animals. Repetitive behaviors and increased pain sensitivity are often comorbid in psychiatric disorders (e.g., autism spectrum disorder). Therefore, the behavioral characteristics of intraperitoneal NMDA-administered mice described herein may be valuable for studying the mechanisms underlying relevant disorders and screening candidate therapeutic molecules.

Comparative evaluation of various analgesic drugs in Wistar rats used as a teaching tool to teach animal experiments to post graduate MD Pharmacology students

Background: Postgraduates when join Pharmacology department, they don’t have much idea about guidelines and methods to do animal experiments. This study was designed to sensitize postgraduate students to animal experiments by evaluating the anti-inflammatory effects and the efficacy of diclofenac, tramadol and etoricoxib in reducing paw edema in wistar rats.Methods: The wistar rats of 225-250gram were divided into four groups (n=10 each). In all the groups the paw edema on right paw was created using 0.1ml of 1% formalin subcutaneously. Group 1 rats (control), group 2 were given diclofenac, group 3 were given tramadol and group 4 were given etoricoxib orally. The parameters assessed were water displacement in plethysmography after 2, 4, 24, 48 hours of giving the drug. The circumference of edematous paws after 4 hours, licking of paw was observed over 30minutes of giving the drug and was compared. Pre and post study feedback were obtained from the students by using a preformed questionnaire to assess the knowledge gained by the students.Results: The test showed that all the drugs were effective in reducing inflammation, circumference of edema and the licking duration significantly (p<0.05). The post study answering of questions by postgraduate was 100% in comparison to pre-study answering which was 33%.Conclusions: A short animal study conducted as a teaching tool to postgraduate students was able to teach the guidelines of animal experiments and handling of animals effectively.

The Analgesic Effects Of Ginger-Juice (Zingiber Officinale Roscoe) On Wistar Albino Rat.

Background: In the view of contradictory reporting concerning analgesic effect, it was planned to investigate the analgesic effect of ginger-juice (ZINGIBER OFFICINALE ROSCOE) on wistar albino rat. Methodology: Wistar albino rats (n=6-12) were administered ginger juice (GJ) at doses (4ml/rat, p.o) as single administration (single dose) and repeated dose over a period of 7 days. Effect of treatment with G.J single and repeated (7days) dose was assessed. Parameter used during assessment was licking of paw after placing the rate on analgesiometer heated up to 50C. Results: The single and repeated administration of GJ (4ml/rat,p.o for 7 days) did not indicate analgesic effect on hot plate model. Conclusion: administered itself did not show analgesic effect on hot plate model.

Dermatite por lambedura em bovinos no estado do Pará / Licking dermatitis in cattle in the state of Pará, Brazil

Foi estudada uma doença em 13 bovinos de 10 propriedades localizadas em seis municípios do estado do Pará, caracterizada por feridas ulcerativas da pele. A doença foi observada somente em regiões do corpo, aos quais os animais tinham acesso com a própria língua; também foi observado que os animais lambiam as feridas com freqüência. Os estudos epidemiológicos e patológicos desses casos, bem como o descarte dos diagnósticos diferenciais, permitiram concluir que se trata de dermatite por lambedura. Essas feridas sararam após a realização da contenção da cabeça dos animais, que desta maneira ficaram impossibilitados de lamber as mesmas.

A condition of 13 cattle from 10 farms in six districts in the state of Pará, Brazil, characterized by ulcerative skin wounds was studied. The lesions were observed in regions of the body to which the cattle had access with their own tongue; the animals licked the wounds frequently. Epidemiological studies, pathological findings and the differential diagnosis indicate that the dermatitis is caused by licking. The wounds healed after restraining the head of the animals that then were unable to lick themselves.