Suppression of excitatory synaptic transmission in the centrolateral amygdala via presynaptic histamine H3 heteroreceptors.

The central histaminergic system has a pivotal role in emotional regulation and psychiatric disorders, including anxiety, depression and schizophrenia. However, the effect of histamine on neuronal activity of the centrolateral amygdala (CeL), an essential node for fear and anxiety processing, remains unknown. Here, using immunostaining and whole-cell patch clamp recording combined with optogenetic manipulation of histaminergic terminals in CeL slices prepared from histidine decarboxylase (HDC)-Cre rats, we show that histamine selectively suppresses excitatory synaptic transmissions, including glutamatergic transmission from the basolateral amygdala, on both PKC-δ- and SOM-positive CeL neurons. The histamine-induced effect is mediated by H3 receptors expressed on VGLUT1-/VGLUT2-positive presynaptic terminals in CeL. Furthermore, optoactivation of histaminergic afferent terminals from the hypothalamic tuberomammillary nucleus (TMN) also significantly suppresses glutamatergic transmissions in CeL via H3 receptors. Histamine neither modulates inhibitory synaptic transmission by presynaptic H3 receptors nor directly excites CeL neurons by postsynaptic H1, H2 or H4 receptors. These results suggest that histaminergic afferent inputs and presynaptic H3 heteroreceptors may hold a critical position in balancing excitatory and inhibitory synaptic transmissions in CeL by selective modulation of glutamatergic drive, which may not only account for the pathophysiology of psychiatric disorders but also provide potential psychotherapeutic targets. KEY POINTS: Histamine selectively suppresses the excitatory, rather than inhibitory, synaptic transmissions on both PKC-δ- and SOM-positive neurons in the centrolateral amygdala (CeL). H3 receptors expressed on VGLUT1- or VGLUT2-positive afferent terminals mediate the suppression of histamine on glutamatergic synaptic transmission in CeL. Optogenetic activation of hypothalamic tuberomammillary nucleus (TMN)-CeL histaminergic projections inhibits glutamatergic transmission in CeL via H3 receptors.

[Evaluation of masticatory efficiency of lingualized occlusal complete denture].

PURPOSE: To compare the masticatory efficiency of lingualized occlusal complete denture with that of semi-anatomical occlusal complete denture. METHODS: Sixty cases with flat or depressed residual ridges were selected from 2009 to 2011. After randomly divided into two groups, the patients were treated with lingualized and semi-anatomical occlusal complete dentures, respectively. A comparative study of masticatory efficiency was carried out on patients wearing lingualized occlusal complete dentures with those wearing semi-anatomical occlusal complete dentures in different period (1st, 2nd, 3rd, 6th month) after wearing. SAS6.16 software package was used for data analysis. RESULTS: Once masticatory time or masticatory times were fixed, there was no significant difference between lingualized occlusal dentures and semi-anatomical occlusal complete dentures (P>0.05). CONCLUSION: Lingualized occlusal complete denture can achieve good masticatory efficiency for edentulous patients with flat or depressed residual ridges.

[Comparative adaptation of crowns of selective laser melting and wax-lost-casting method].

OBJECTIVE: To investigate the marginal adaptation of crowns fabricated by selective laser melting (SLM) and wax-lost-casting method, so as to provide an experimental basis for clinic. METHODS: Co-Cr alloy full crown were fabricated by SLM and wax-lost-casting for 24 samples in each group. All crowns were cemented with zinc phosphate cement and cut along longitudinal axis by line cutting machine. The gap between crown tissue surface and die was measured by 6-point measuring method with scanning electron microscope (SEM). The marginal adaptation of crowns fabricated by SLM and wax-lost-casting were compared statistically. RESULTS: The gap between SLM crowns were (36.51 ± 2.94), (49.36 ± 3.31), (56.48 ± 3.35), (42.20 ± 3.60) µm, and wax-lost-casting crowns were (68.86 ± 5.41), (58.86 ± 6.10), (70.62 ± 5.79), (69.90 ± 6.00) µm. There were significant difference between two groups (P < 0.05). CONCLUSIONS: Co-Cr alloy full crown fabricated by wax-lost-casting method and SLM method provide acceptable marginal adaptation in clinic, and the marginal adaptation of SLM is better than that of wax-lost-casting method.

[Study of the appearance difference of lower complete denture between functional and anatomic impression techniques].

PURPOSE: To compare the difference in oblique external ridge, oblique internal ridge and alveolar process crest of lower complete denture base made through functional impression and anatomic impression techniques. METHODS: Fifteen patients were chosen to treat with two kinds of complete dentures through functional impression and anatomic impression technique respectively. 3D laser scanner was used to scan the three-dimensional model of the denture base and the differences of the surface structural between two techniques in alveolar process crest, external and internal oblique ridges were analyzed, using paired t test with SPSS 12.0 software package. RESULTS: Between the two techniques, there were significant differences in the areas of internal and external oblique ridge(P<0.01); there was no significant difference in the main support areas(P>0.05). CONCLUSIONS: The results explain why there is less tenderness when functional impression technique is applied. The differences measured also indicate that sufficient buffering should be made in external and internal oblique ridge areas in clinic.

[The stress distribution of mandibular alveolar mucosa under functional impressive complete denture studied by 3-D finite element analysis].

PURPOSE: To analyze the stress distribution and displacement of the mandibular alveolar mucosa under functional impressive complete denture. METHODS: CT images were processed by Mimics and Geomagic studio, and the solid models and 3-D finite element models were established by Unigraphics NX. 3-D finite element analysis (3-D FEA) was used to study the stress distribution and displacement on the mandibular alveolar mucosa under functional impressive complete denture and anatomic impressive complete denture. RESULTS: The stress distribution on the mandibular alveolar mucosa under two types of complete denture were consistent, and arranged from large to small order as follow: alveolar process crest of molar area, alveolar process crest of anterior area, external oblique ridge and internal oblique ridge. At alveolar process crest and internal oblique ridge, the stress and Z-axis displacement of functional impressive complete denture were less than those of anatomic impressive complete denture. CONCLUSIONS: During masticatory period, the stress distribution on the mandibular alveolar mucosa under functional impressive complete denture is more even and more comprehensive than that under anatomic one.