Hyperexcitation of ovBNST CRF neurons during stress contributes to female-biased expression of anxiety-like avoidance behaviors.

Corticotropin releasing factor (CRF) network in the oval nucleus of bed nuclei of the stria terminalis (ovBNST) is generally indicated in stress, but its role in female-biased susceptibility to anxiety is unknown. Here, we established a female-biased stress paradigm. We found that the CRF release in ovBNST during stress showed female-biased pattern, and ovBNST CRF neurons were more prone to be hyperexcited in female mice during stress in both in vitro and in vivo studies. Moreover, optogenetic modulation to exchange the activation pattern of ovBNST CRF neurons during stress between female and male mice could reverse their susceptibility to anxiety. Last, CRF receptor type 1 (CRFR1) mediated the CRF-induced excitation of ovBNST CRF neurons and showed female-biased expression. Specific knockdown of the CRFR1 level in ovBNST CRF neurons in female or overexpression that in male could reverse their susceptibility to anxiety. Therefore, we identify that CRFR1-mediated hyperexcitation of ovBNST CRF neurons in female mice encode the female-biased susceptibility to anxiety.

Suppression of HCN channels in the spinal dorsal horn restores KCC2 expression and attenuates diabetic neuropathic pain.

Previous studies have shown that the hyperpolarized cyclic nucleotide gated (HCN) ion channels in the spinal dorsal horn (SDH) might be involved in the development of diabetic neuropathic pain (DNP). Additionally, other studies have shown that the decreased potassium-chloride cotransporter 2 (KCC2) expression in the SDH promotes pain hypersensitivity. Both HCN channels and KCC2 were highly expressed in spinal substantia gelatinosa neurons. However, whether the K+ efflux induced by the activation of HCN channels in DNP modulate KCC2 function and subsequently affect the role of γ-aminobutyric acid (GABA)/GABA-A receptors of neurons in the SDH remains to be clarified. The purpose of this work was to investigate the underlying mechanisms of KCC2 participating in HCN channels to promote DNP. Here, we found that the analgesic role of HCN channels blocker ZD7288 was associated with the up-regulated KCC2 expression and could be prevented by DIOA, a KCC2 blocker. Furthermore, the level of GABA in DNP rats significantly increased, which was decreased by ZD72288. Moreover, DIOA pretreatment could partly block the inhibitory effect of ZD7288 on the cyclic adenosine monophosphate-protein kinase A (cAMP-PKA) signaling activation of DNP rats. Finally, inhibition of cAMP-PKA signaling alleviated allodynia and elevated KCC2 expression in DNP rats. Altogether, this study reveals that the role of cAMP-PKA signaling-regulated HCN channels in DNP associated with decreased KCC2 expression in the spinal cord and altered GABA nature.

cAMP-PKA signaling is involved in regulation of spinal HCN channels function in diabetic neuropathic pain.

The cyclic adenosine monophosphate-protein kinase A (cAMP-PKA) signaling acts a pivotal part in hyperpolarization-activated cyclic nucleotide-gated (HCN) channels-mediated neuropathic and inflammatory pain. However, there has been no evidence of cAMP-PKA signaling is involved in regulation of spinal HCN channels function in the occurrence of diabetic neuropathic pain (DNP). The study aimed to elucidate the impact of HCN channels on neuropathic pain in a rat model of diabetes induced by streptozotocin, and whether cAMP-PKA signaling is involved in regulation of HCN channels function. In this report, we evaluated the effect of intrathecal administration of HCN channel blockers ZD7288, cAMP inhibitor SQ22536 and PKA inhibitor H-89 on nociceptive behavior in DNP rats. The mechanical withdrawal threshold (MWT) was measured to evaluate pain behavior in rats. Protein expression levels of HCN2, HCN4 channels and PKA in the spinal dorsal horn of rats were assessed. Furthermore, the levels of cAMP in rat spinal dorsal horn was analyzed. We discovered that DNP rats showed significant mechanical allodynia and are related to the increased HCN2 and HCN4 channels expression, enhanced cAMP production and elevated the expression of PKA protein in the spinal dorsal horn, which were attenuated by intrathecal ZD7288. Furthermore, intrathecal injection of SQ22536 and H-89 significantly reduced the HCN2 and HCN4 channels expression in the spinal dorsal horn of DNP rats. Our findings indicate that HCN channels of the spinal dorsal horn participate in the pathogenesis of allodynia in rats with DNP, which could be regulated by cAMP-PKA signaling. Therefore, HCN channels and cAMP-PKA signaling are potential targets for hyperalgesia treatment in DNP patients.

Formulation and evaluation of a topical liposomal gel containing a combination of zedoary turmeric oil and tretinoin for psoriasis activity.

This study was to develop a combination of zedoary turmeric oil (ZTO) and tretinoin (TRE)-loaded liposomal gel as a topical drug delivery system. We used a combination of single-factor experiment and orthogonal experiment to systematically optimize encapsulation process of the compound liposomes. The optimized liposome vesicles were incorporated into Carbopol gel matrix and studied by continuous in vitro (skin penetration and retention) and in vivo (anti-psoriatic activity using mouse vaginal model and mouse tail model) experiments. The optimized liposomes had an entrapment efficiency (EE) of ZTO was (64.63 ± 1.00)%, EE of TRE was (90.33 ± 0.72)%, drug loading (DL) of ZTO was (9.09 ± 0.14)%, DL of TRE was (1.43 ± 0.02)%, particle size of 257.41 ± 7.58 nm, polydispersity index (PDI) of 0.10 ± 0.04 and zeta potential of -38.77 ± 0.81 mV. Transmission electron microscopy showed liposomes had a regular spherical surface. After 1-month storage at (4 ± 2)°C, the optimized liposome preparations maintained its stability. In vitro study indicated that liposome formulations could significantly prolong the penetration of drugs into the hair follicles of mice and keep more drugs in the skin compared with conventional gel formulations. In vivo study showed that liposomal gel was more effective than conventional gel in treating psoriasis and had a significant dose-dependent effect on psoriasis. In summary, liposomal gel is expected to be an ideal carrier for topical drug delivery systems of ZTO and TRE.