Silencing of the T-type voltage-gated calcium channel α1 subunit by fungus-mediated RNAi altered the structure of F-actin and caused defective behaviors in Ditylenchus destructor.

BACKGROUND: T-type calcium channels, characterized as low-voltage activated (LVA) calcium channels, play crucial physiological roles across a wide range of tissues, including both the neuronal and nonneuronal systems. Using in situ hybridization and RNA interference (RNAi) techniques in vitro, we previously identified the tissue distribution and physiological function of the T-type calcium channel α1 subunit (DdCα1G) in the plant-parasitic nematode Ditylenchus destructor. METHODS AND RESULTS: To further characterize the functional role of DdCα1G, we employed a combination of immunohistochemistry and fungus-mediated RNAi and found that DdCα1G was clearly distributed in stylet-related tissue, oesophageal gland-related tissue, secretory-excretory duct-related tissue and male spicule-related tissue. Silencing DdCα1G led to impairments in the locomotion, feeding, reproductive ability and protein secretion of nematodes. To confirm the defects in behavior, we used phalloidin staining to examine muscle changes in DdCα1G-RNAi nematodes. Our observations demonstrated that defective behaviors are associated with related muscular atrophy. CONCLUSION: Our findings provide a deeper understanding of the physiological functions of T-type calcium channels in plant-parasitic nematodes. The T-type calcium channel can be considered a promising target for sustainable nematode management practices.

Elevated microRNA-214-3p level ameliorates neuroinflammation after spinal cord ischemia-reperfusion injury by inhibiting Nmb/Cav3.2 pathway.

BACKGROUND: Neuromedin B (Nmb) plays a pivotal role in the transmission of neuroinflammation, particularly during spinal cord ischemia-reperfusion injury (SCII). However, the detailed molecular mechanisms underlying this process remain elusive. METHODS: The SCII model was established by clamping the abdominal aorta of male Sprague-Dawley (SD) rats for 60 min. The protein expression levels of Nmb, Cav3.2, and IL-1ß were detected by Western blotting, while miR-214-3p expression was quantified by qRT-PCR. The targeted regulation between miR-214-3p and Nmb was investigated using a dual-luciferase reporter gene assay. The cellular localization of Nmb and Cav3.2 with cell-specific markers was visualized by immunofluorescence staining. The specific roles of miR-214-3p on the Nmb/Cav3.2 interactions in SCII-injured rats were explored by intrathecal injection of Cav3.2-siRNA, PD168368 (a specific NmbR inhibitor) and synthetic miR-214-3p agomir and antagomir in separate experiments. Additionally, hind-limb motor function was evaluated using the modified Tarlov scores. RESULTS: Compared to the Sham group, the protein expression levels of Nmb, Cav3.2, and the proinflammatory factor Interleukin(IL)-1ß were significantly elevated at 24 h post-SCII. Intrathecal injection of PD168368 and Cav3.2-siRNA significantly suppressed the expression of Cav3.2 and IL-1ß compared to the SCII group. The miRDB database and dual-luciferase reporter gene assay identified Nmb as a direct target of miR-214-3p. As expected, in vivo overexpression of miR-214-3p by agomir-214-3p pretreatment significantly inhibited the increases in Nmb, Cav3.2 and IL-1ß expression and improved lower limb motor function in SCII-injured rats, while antagomiR-214-3p pretreatment reversed these effects. CONCLUSIONS: Nmb protein levels positively correlated with Cav3.2 expression in SCII rats. Upregulating miR-214-3p ameliorated hind-limb motor function and protected against neuroinflammation via inhibiting the aberrant Nmb/Cav3.2 interactions and downstream IL-1ß release. These findings provide novel therapeutic targets for clinical prevention and treatment of SCII.

Cav3.2 T-Type Calcium Channel Mediates Acute Itch and Contributes to Chronic Itch and Inflammation in Experimental Atopic Dermatitis.

Voltage-gated calcium channels regulate neuronal excitability. The Cav3.2 isoform of the T-type voltage-activated calcium channel is expressed in sensory neurons and is implicated in pain transmission. However, its role in itch remains unclear. In this study, we demonstrated that Cav3.2 is expressed by mechanosensory and peptidergic subsets of mouse dorsal root ganglion neurons and colocalized with TRPV1 and receptors for type 2 cytokines. Cav3.2-positive neurons innervate human skin. A deficiency of Cav3.2 reduces histamine, IL-4/IL-13, and TSLP-induced itch in mice. Cav3.2 channels were upregulated in the dorsal root ganglia of an atopic dermatitis (AD)-like mouse model and mediated neuronal excitability. Genetic knockout of Cav3.2 or T-type calcium channel blocker mibefradil treatment reduced spontaneous and mechanically induced scratching behaviors and skin inflammation in an AD-like mouse model. Substance P and vasoactive intestinal polypeptide levels were increased in the trigeminal ganglia from AD-like mouse model, and genetic ablation or pharmacological inhibition of Cav3.2 reduced their gene expression. Cav3.2 knockout also attenuated the pathologic changes in ex vivo skin explants cocultured with trigeminal ganglia neurons from AD-induced mice. Our study identifies the role of Cav3.2 in both histaminergic and nonhistaminergic acute itch. Cav3.2 channel also contributes to AD-related chronic itch and neuroinflammation.

The relationship of promoter methylation of calcium voltage-gated channel alpha 1 and interleukin-16 to primary osteoarthritis.

OBJECTIVE: Osteoarthritis is the most prevalent joint disease worldwide and the primary cause of musculoskeletal dysfunction. Epigenetic changes in various genes, particularly methylation, have been implicated as possible underlying causes of primary osteoarthritis. The aim of our study was to investigate the promoter methylation status of the calcium voltage-gated channel alpha 1 subunit G (CACNA1G) and interleukin-16 (IL-16) genes, which are strongly associated with calcium channel activity and antigen presentation, respectively, in primary osteoarthritis patients. PATIENTS AND METHODS: Twenty-one patients with primary osteoarthritis and 25 healthy controls were included in our study. The methylation status of CACNA1G and IL-16 genes was analyzed with methylation-specific Polymerase Chain Reaction (PCR), and the serum levels of IL-16 were determined with Enzyme-Linked Immunosorbent Assay (ELISA). RESULTS: The age of the patients was 63.95±8.41 years, and they were 15 females and 6 males. The promoter of the CACNA1G gene was found to be hypermethylated in primary osteoarthritis patients (p<0.001). In contrast, the promoter of the IL-16 gene was found to be hypomethylated compared to the control (p<0.001). The serum levels of IL-16 increased in parallel with the hypomethylated promoter status of IL-16 gene in primary osteoarthritis patients compared to the control (p<0.001). CONCLUSIONS: Our study indicates that the methylation status of CACNA1G and IL-16 gene promoters are epigenetically altered in patients with primary osteoarthritis. Moreover, increased serum IL-16 levels in osteoarthritis patients may be associated with hypomethylation of the IL-16 gene promoter.

Secretory carrier-associated membrane protein 5 regulates cell-surface targeting of T-type calcium channels.

Missense mutations in the human secretary carrier-associated membrane protein 5 (SCAMP5) cause a variety of neurological disorders including neurodevelopmental delay, epilepsy, and Parkinson's disease. We recently documented the importance of SCAMP2 in the regulation of T-type calcium channel expression in the plasma membrane. Here, we show that similar to SCAMP2, the co-expression of SCAMP5 in tsA-201 cells expressing recombinant Cav3.1, Cav3.2, and Cav3.3 channels nearly abolished whole-cell T-type currents. Recording of intramembrane charge movements revealed that SCAMP5-induced inhibition of T-type currents is primarily caused by the reduced expression of functional channels in the plasma membrane. Moreover, we show that SCAMP5-mediated downregulation of Cav3.2 channels is essentially preserved with disease-causing SCAMP5 R91W and G180W mutations. Hence, this study extends our previous findings with SCAMP2 and indicates that SCAMP5 also contributes to repressing the expression of T-type channels in the plasma membrane.

CaV3.2 (CACNA1H) in Primary Aldosteronism.

Aldosterone is a steroid hormone produced in the zona glomerulosa (ZG) of the adrenal cortex. The most prominent function of aldosterone is the control of electrolyte homeostasis and blood pressure via the kidneys. The primary factors regulating aldosterone synthesis are the serum concentrations of angiotensin II and potassium. The T-type voltage-gated calcium channel CaV3.2 (encoded by CACNA1H) is an important component of electrical as well as intracellular calcium oscillations, which govern aldosterone production in the ZG. Excessive aldosterone production that is (partially) uncoupled from physiological stimuli leads to primary aldosteronism, the most common cause of secondary hypertension. Germline gain-of-function mutations in CACNA1H were identified in familial hyperaldosteronism, whereas somatic mutations are a rare cause of aldosterone-producing adenomas. In this review, we summarize these findings, put them in perspective, and highlight missing knowledge.

Cav3.2-dependent hyperalgesia/allodynia following intrathecal and intraplantar zinc chelator administration in rodents.

Cav3.2, a T-type calcium channel (T-channel) family member, is expressed in the nociceptors and spinal cord, and its activity is largely suppressed by zinc under physiological conditions. In rats, intrathecal and intraplantar administration of a zinc chelator, TPEN, caused T-channel-dependent mechanical hyperalgesia, and the intraplantar, but not intrathecal, TPEN induced Cav3.2 upregulation in the dorsal root ganglion. In mice, intraplantar TPEN also caused mechanical allodynia, which was abolished by T-channel inhibitors or Cav3.2 gene deletion. Together, spinal and peripheral zinc deficiency appears to enhance Cav3.2 activity in the spinal postsynaptic neurons and nociceptors, respectively, thereby promoting pain.

Electrophysiological characterization of a CaV3.1 calcium channel mutation linked to trigeminal neuralgia.

Trigeminal neuralgia is a rare and debilitating disorder that affects one or more branches of the trigeminal nerve, leading to severe pain attacks and a poor quality of life. It has been reported that the CaV3.1 T-type calcium channel may play an important role in trigeminal pain and a recent study identified a new missense mutation in the CACNA1G gene that encodes the pore forming α1 subunit of the CaV3.1 calcium channel. The mutation leads to a substitution of an Arginine (R) by a Glutamine (Q) at position 706 in the I-II linker region of the channel. Here, we used whole-cell voltage-clamp recordings to evaluate the biophysical properties of CaV3.1 wild-type and R706Q mutant channels expressed in tsA-201 cells. Our data indicate an increase in current density in the R706Q mutant, leading to a gain-of-function effect, without changes in the voltage for half activation. Moreover, voltage clamp using an action potential waveform protocol revealed an increase in the tail current at the repolarization phase in the R706Q mutant. No changes were observed in the voltage-dependence of inactivation. However, the R706Q mutant displayed a faster recovery from inactivation. Hence, the gain-of-function effects in the R706Q CaV3.1 mutant have the propensity to impact pain transmission in the trigeminal system, consistent with a contribution to trigeminal neuralgia pathophysiology.

[Changes in Expression of Genes Associated with Calcium Processes in the Hippocampus in Mice Exposed to Chronic Social Stress].

Whole-transcriptome data were used to study the changes in expression of genes coding proteins involved in the calcium regulation processes in the hippocampus of male mice with symptoms of depression caused by chronic social defeat stress. Cacna1g, Cacnb3, Camk1g, Camk2d, Camk2n2, Caly, Caln1, S100a16, and Slc24a4 genes were upregulated in the hippocampus of depressed mice compared to a control, while Cacna2d1, Cacng5, Grin2a, and Calm2 were downregulated. The greatest number of significant correlations was observed between the expression level of Calm2, which showed the highest transcriptional activity, and other differentially expressed genes. Calcium signaling in the hippocampus was assumed to be disrupted in mice exposed to chronic social defeat stress. The involvement of Calm2, Camk1g, Camk2d, and Camk2n2 genes in the process is discussed.

CaV3.3 Channelopathies.

CaV3.3 is the third member of the low-voltage-activated calcium channel family and the last to be recognized as disease gene. Previously, CACNA1I, the gene encoding CaV3.3, had been described as schizophrenia risk gene. More recently, de novo missense mutations in CACNA1I were identified in patients with variable degrees of neurodevelopmental disease with and without epilepsy. Their functional characterization indicated gain-of-function effects resulting in increased calcium load and hyperexcitability of neurons expressing CaV3.3. The amino acids mutated in the CaV3.3 disease variants are located in the vicinity of the channel's activation gate and thus are classified as gate-modifying channelopathy mutations. A persistent calcium leak during rest and prolonged calcium spikes due to increased voltage sensitivity of activation and slowed kinetics of channel inactivation, respectively, may be causal for the neurodevelopmental defects. The prominent expression of CaV3.3 in thalamic reticular nucleus neurons and its essential role in generating the rhythmic thalamocortical network activity are consistent with a role of the mutated channels in the etiology of epileptic seizures and thus suggest T-type channel blockers as a viable treatment option.

Paroxysmal Tonic Upgaze in a Patient With Congenital Ataxia due to a De Novo Missense Variant of CACNA1G.

BACKGROUND: Paroxysmal tonic upgaze (PTU), defined as an involuntary upward movement of the eyes, has been considered as a benign phenomenon but may also be associated with ataxia and developmental delay. To date, CACNA1G mutations have been reported in autosomal dominant spinocerebellar ataxia designated SCA42 and in early encephalopathies with cerebellar atrophy but never in periodic childhood manifestations of PTU type. METHODS AND RESULTS: We report the case of a two-month-old infant with a de novo pathogenic variation of CACNA1G who presented with PTU associated with congenital ataxia and other periodic neurological manifestations. CONCLUSIONS: Although the link between CACNA1G mutations and periodic neurological manifestations remains unclear, we provide detailed video documentations of PTU, paroxysmal torticollis, and ataxia in a patient with a CACNA1G mutation. This case allows a better understanding of the underlying mechanisms of PTU and suggests potential new avenues for clinical treatments.

Opioid-induced hyperalgesia: Are thalamic T-type calcium channels treatment targets?

Opioid-induced hyperalgesia (OIH) is a state of paradoxically enhanced pain transmission, termed nociceptive sensitization, described to occur in both humans and animals after repeated administration of opioid drugs, including rapidly acting remifentanil. However, molecular mechanisms of OIH remain understudied. In this issue of the JCI, Yan Jin and colleagues provided strong evidence that hyperexcitable thalamocortical networks drive remifentanil-induced hyperalgesia in a rodent model of postsurgical pain. Furthermore, the authors specifically identified an important role of the CaV3.1 isoform of low-voltage-activated or T-type calcium channels (T-channels) in this process. Further experiments are needed to determine whether thalamic T channels could serve as targets for the treatment of OIH.

Thalamocortical circuits drive remifentanil-induced postoperative hyperalgesia.

Remifentanil-induced hyperalgesia (RIH) is a severe but common postoperative clinical problem with elusive underlying neural mechanisms. Here, we discovered that glutamatergic neurons in the thalamic ventral posterolateral nucleus (VPLGlu) exhibited significantly elevated burst firing accompanied by upregulation of Cav3.1 T-type calcium channel expression and function in RIH model mice. In addition, we identified a glutamatergic neuronal thalamocortical circuit in the VPL projecting to hindlimb primary somatosensory cortex glutamatergic neurons (S1HLGlu) that mediated RIH. In vivo calcium imaging and multi-tetrode recordings revealed heightened S1HLGlu neuronal activity during RIH. Moreover, preoperative suppression of Cav3.1-dependent burst firing in VPLGlu neurons or chemogenetic inhibition of VPLGlu neuronal terminals in the S1HL abolished the increased S1HLGlu neuronal excitability while alleviating RIH. Our findings suggest that remifentanil induces postoperative hyperalgesia by upregulating T-type calcium channel-dependent burst firing in VPLGlu neurons to activate S1HLGlu neurons, thus revealing an ion channel-mediated neural circuit basis for RIH that can guide analgesic development.

Centrally expressed Cav3.2 T-type calcium channel is critical for the initiation and maintenance of neuropathic pain.

Cav3.2 T-type calcium channel is a major molecular actor of neuropathic pain in peripheral sensory neurons, but its involvement at the supraspinal level is almost unknown. In the anterior pretectum (APT), a hub of connectivity of the somatosensory system involved in pain perception, we show that Cav3.2 channels are expressed in a subpopulation of GABAergic neurons coexpressing parvalbumin (PV). In these PV-expressing neurons, Cav3.2 channels contribute to a high-frequency-bursting activity, which is increased in the spared nerve injury model of neuropathy. Specific deletion of Cav3.2 channels in APT neurons reduced both the initiation and maintenance of mechanical and cold allodynia. These data are a direct demonstration that centrally expressed Cav3.2 channels also play a fundamental role in pain pathophysiology.

The T-type calcium channel CaV3.2 regulates insulin secretion in the pancreatic ß-cell.

Voltage-gated Ca2+ (CaV) channel dysfunction leads to impaired glucose-stimulated insulin secretion in pancreatic ß-cells and contributes to the development of type-2 diabetes (T2D). The role of the low-voltage gated T-type CaV channels in ß-cells remains obscure. Here we have measured the global expression of T-type CaV3.2 channels in human islets and found that gene expression of CACNA1H, encoding CaV3.2, is negatively correlated with HbA1c in human donors, and positively correlated with islet insulin gene expression as well as secretion capacity in isolated human islets. Silencing or pharmacological blockade of CaV3.2 attenuates glucose-stimulated cytosolic Ca2+ signaling, membrane potential, and insulin release. Moreover, the endoplasmic reticulum (ER) Ca2+ store depletion is also impaired in CaV3.2-silenced ß-cells. The linkage between T-type (CaV3.2) and L-type CaV channels is further identified by the finding that the intracellular Ca2+ signaling conducted by CaV3.2 is highly dependent on the activation of L-type CaV channels. In addition, CACNA1H expression is significantly associated with the islet predominant L-type CACNA1C (CaV1.2) and CACNA1D (CaV1.3) genes in human pancreatic islets. In conclusion, our data suggest the essential functions of the T-type CaV3.2 subunit as a mediator of ß-cell Ca2+ signaling and membrane potential needed for insulin secretion, and in connection with L-type CaV channels.

µ-Theraphotoxin Pn3a inhibition of CaV3.3 channels reveals a novel isoform-selective drug binding site.

Low voltage-activated calcium currents are mediated by T-type calcium channels CaV3.1, CaV3.2, and CaV3.3, which modulate a variety of physiological processes including sleep, cardiac pace-making, pain, and epilepsy. CaV3 isoforms' biophysical properties, overlapping expression, and lack of subtype-selective pharmacology hinder the determination of their specific physiological roles in health and disease. We have identified µ-theraphotoxin Pn3a as the first subtype-selective spider venom peptide inhibitor of CaV3.3, with >100-fold lower potency against the other T-type isoforms. Pn3a modifies CaV3.3 gating through a depolarizing shift in the voltage dependence of activation thus decreasing CaV3.3-mediated currents in the normal range of activation potentials. Paddle chimeras of KV1.7 channels bearing voltage sensor sequences from all four CaV3.3 domains revealed preferential binding of Pn3a to the S3-S4 region of domain II (CaV3.3DII). This novel T-type channel pharmacological site was explored through computational docking simulations of Pn3a, site-directed mutagenesis, and full domain II swaps between CaV3 channels highlighting it as a subtype-specific pharmacophore. This research expands our understanding of T-type calcium channel pharmacology and supports the suitability of Pn3a as a molecular tool in the study of the physiological roles of CaV3.3 channels.

A Novel Somatic Mutation of CACNA1H p.V1937M in Unilateral Primary Hyperaldosteronism.

Background: Somatic mutations for excess aldosterone production have been frequently identified as important roles in the pathogenesis of unilateral primary hyperaldosteronism (uPA). Although CACNA1H mutation represents a minor etiology in primary aldosteronism, it plays a significant role in causing uPAs in sporadic cases. Objective: To identify novel somatic CACNA1H mutation in patients with uPA and investigate the pathophysiological, immunohistological, and clinical characteristics of the variant. Methods: We applied a customized and targeted gene panel next-generation sequencing approach to detect mutations from the uPA cohort in Taiwan Primary Aldosteronism Investigation study group. Information from pre-diagnostic to postoperative data was collected, including past history, medications, blood pressure readings, biochemical data, and image studies. The functional role of the variant was confirmed by in vitro studies, demonstrating aldosterone production in variant-transfected human adrenal cell lines. Results: We identified a novel somatic CACNA1H mutation c.5809G>A (p.Val1937Met) in a uPA case. The CACNA1H gene encodes the pore-forming alpha-1H subunit of the voltage-dependent T-type calcium channel Cav3.2. This somatic CACNA1H p.V1937M variant showed excellent clinical and biochemical outcomes after ipsilateral adrenalectomy. The functional effect of somatic CACNA1H p.V1937M variant results in increased CYP11B2 expression and aldosterone biosynthesis in HAC15 cells. A distinct heterogeneous foamy pattern of CYP11B2 and CYP17A1 expression was identified in immunohistological staining, supporting the pathological evidence of aldosterone synthesis. Conclusions: The somatic mutation of CACNA1H p.V1937M might be a pathogenic driver in aldosterone overproduction. This study provides new insight into the molecular mechanism and disease outcomes of uPA.

Rare CACNA1H and RELN variants interact through mTORC1 pathway in oligogenic autism spectrum disorder.

Oligogenic inheritance of autism spectrum disorder (ASD) has been supported by several studies. However, little is known about how the risk variants interact and converge on causative neurobiological pathways. We identified in an ASD proband deleterious compound heterozygous missense variants in the Reelin (RELN) gene, and a de novo splicing variant in the Cav3.2 calcium channel (CACNA1H) gene. Here, by using iPSC-derived neural progenitor cells (NPCs) and a heterologous expression system, we show that the variant in Cav3.2 leads to increased calcium influx into cells, which overactivates mTORC1 pathway and, consequently, further exacerbates the impairment of Reelin signaling. Also, we show that Cav3.2/mTORC1 overactivation induces proliferation of NPCs and that both mutant Cav3.2 and Reelin cause abnormal migration of these cells. Finally, analysis of the sequencing data from two ASD cohorts-a Brazilian cohort of 861 samples, 291 with ASD; the MSSNG cohort of 11,181 samples, 5,102 with ASD-revealed that the co-occurrence of risk variants in both alleles of Reelin pathway genes and in one allele of calcium channel genes confer significant liability for ASD. Our results support the notion that genes with co-occurring deleterious variants tend to have interconnected pathways underlying oligogenic forms of ASD.

Cav 3.2 T-type calcium channel regulates mouse platelet activation and arterial thrombosis.

BACKGROUND: Cav 3.2 is a T-type calcium channel that causes low-threshold exocytosis. T-type calcium channel blockers reduce platelet granule exocytosis and aggregation. However, studies of the T-type calcium channel in platelets are lacking. OBJECTIVE: To examine the expression and role of Cav 3.2 in platelet function. METHODS: Global Cav 3.2-/- and platelet-specific Cav 3.2-/- mice and littermate controls were used for this study. Western blot analysis was used to detect the presence of Cav 3.2 and activation of the calcium-responsive protein extracellular signal-regulated kinase (ERK). Fura-2 dye was used to assess platelet calcium. Flow cytometry and light transmission aggregometry were used to evaluate platelet activation markers and aggregation, respectively. FeCl3 -induced thrombosis and a microfluidic flow device were used to assess in vivo and ex vivo thrombosis, respectively. RESULTS: Cav 3.2 was expressed in mouse platelets. As compared with wild-type controls, Cav 3.2-/- mouse platelets showed reduced calcium influx. Similarly, treatment with the T-type calcium channel inhibitor Ni2+ decreased the calcium influx in wild-type platelets. As compared with controls, both Cav 3.2-/- and Ni2+ -treated wild-type platelets showed reduced activation of ERK. ATP release, P-selectin exposure, and αIIb ß3 activation were reduced in Cav 3.2-/- and Ni2+ -treated wild-type platelets, as was platelet aggregation. On in vivo and ex vivo thrombosis assay, Cav3.2 deletion caused delayed thrombus formation. However, tail bleeding assay showed intact hemostasis. CONCLUSION: These results suggest that Cav 3.2 is required for the optimal activation of platelets.

[Effects of CACNA1H gene knockout on autistic-like behaviors and the morphology of hippocampal neurons in mice].

OBJECTIVE: To investigate the effects of CACNA1H gene knockout (KO) on autistic-like behaviors and the morphology of hippocampal neurons in mice. METHODS: In the study, 25 CACNA1H KO mice of 3-4 weeks old and C57BL/6 background were recruited as the experimental group, and 26 wild type (WT) mice of the same age and background were recruited as the control group. Three-chamber test and open field test were used to observe the social interaction, anxiety, and repetitive behaviors in mice. After that, their brain weight and size were measured, and the number of hippocampal neurons were observed by Nissl staining. Furthermore, the CACNA1H heterozygote mice were interbred with Thy1-GFP-O mice to generate CACNA1H-/--Thy1+(KO-GFP) and CACNA1H+/+-Thy1+ (WT-GFP) mice. The density and maturity of dendritic spines of hippocampal neurons were observed. RESULTS: In the sociability test session of the three-chamber test, the KO mice spent more time in the chamber of the stranger mice than in the object one (F1, 14=95.086, P < 0.05; Post-Hoc: P < 0.05), without any significant difference for the explored preference index between the two groups (t=1.044, P>0.05). However, in the social novelty recognition test session, no difference was observed between the time of the KO mice spend in the chamber of new stranger mice and the stranger one (F1, 14=18.062, P < 0.05; Post-Hoc: P>0.05), and the explored preference index of the KO mice was less than that of the control group (t=2.390, P < 0.05). In the open field test, the KO mice spent less time in the center of the open field apparatus than the control group (t=2.503, P < 0.05), but the self-grooming time was significantly increased compared with the control group (t=-2.299, P < 0.05). Morphological results showed that the brain weight/body weight ratio (t=0.356, P>0.05) and brain size (t=-0.660, P>0.05) of the KO mice were not significantly different from those of the control group, but the number of neurons were significantly reduced in hippocampal dentate gyrus compared with the control group (t=2.323, P < 0.05). Moreover, the density of dendritic spine of dentate gyrus neurons in the KO-GFP mice was significantly increased compared with the control group (t=-2.374, P < 0.05), without any significant difference in spine maturity (t=-1.935, P>0.05). CONCLUSION: CACNA1H KO mice represent autistic-like behavior, which may be related to the decrease in the number of neurons and the increase in the density of dendritic spine in the dentate gyrus.