Sleep-inducing effect of substance P-cholera toxin A subunit in mice

Efficacy and safety of bloodletting puncture and cupping in postherpetic neuralgia: A systematic review and meta‑analysis

The present study aimed to evaluate the efficacy and safety of bloodletting puncture and cupping (BLP-C) in postherpetic neuralgia (PHN) and to provide guidance for clinical treatment. Randomized controlled trials (RCTs) of BLP-C therapy in PHN were systematically searched in eight databases from inception to September 2022. Literature screening, data extraction and quality assessment were performed by two independent researchers. Dichotomous and continuous variables were pooled using the risk ratio (RR) and weighted mean difference (WMD), respectively. A total of 13 studies involving 1,129 patients with PHN (571 in the experimental group and 558 in the control group) were included in the present meta-analysis. Overall efficacy (RR=1.21, 95% CI: 1.15 to 1.28, P<0.00001), VAS score (WMD=-1.10, 95% CI: -1.31 to -0.90, P<0.00001) and PSQI score (WMD=-2.42, 95% CI: -2.87 to -1.96, P<0.0001) were significantly different between the BLP-C group and Western medicine group. Furthermore, subgroup analysis demonstrated that BLP-C alone or combined with other traditional Chinese medicines was more effective than Western medicine in PHN. A total of four RCTs mentioned adverse reactions, most of which were in the Western medicine group and were relieved after treatment discontinuation. In conclusion, BLP-C is superior to Western medicine in relieving pain and improving the sleep quality of patients with PHN with a lower incidence of adverse effects.

An investigation on the changes of serum CCK-8, substance P, and 5-HT in patients with post-stroke insomnia

BACKGROUND

At present, the pathogenesis of post-stroke insomnia (PSI) is still inconclusive.

OBJECTIVE

To explore the changes and significance of serum cholecystokinin-8 (CCK-8), substance P (SP), and 5-hydroxytryptamine (5-HT) in patients with PSI.

METHODS

Ninety-one patients with stroke were selected as the research subjects, and according to the score of the Athens Insomnia Scale (AIS), they were divided into the insomnia group and the non-insomnia group. The serum levels of CCK-8, SP, and 5-HT in the two groups were compared to explore their relationships with PSI.

RESULTS

Among the 91 patients, 56 were in the insomnia group and 35 were in the non-insomnia group, and the incidence of insomnia was 61.5%. There was no significant difference in the serum levels of CCK-8, SP, and 5-HT between the two groups (P= 0.696, 0.980, and 0.809, respectively). One-way analysis of variance showed that there was no significant correlation between the serum levels of CCK-8, SP, 5-HT, and the AIS score (P= 0.7393, 0.9581, and 0.5952, respectively).

CONCLUSION

The incidence of PSI was relatively high, but it could not be proved that CCK-8, SP, and 5-HT were involved in the pathogenesis of PSI. There might exist other neurotransmitters involved in the pathophysiological process of PSI, which should be further explored.

Roles of Neuropeptides in Sleep-Wake Regulation

Sleep and wakefulness are basic behavioral states that require coordination between several brain regions, and they involve multiple neurochemical systems, including neuropeptides. Neuropeptides are a group of peptides produced by neurons and neuroendocrine cells of the central nervous system. Like traditional neurotransmitters, neuropeptides can bind to specific surface receptors and subsequently regulate neuronal activities. For example, orexin is a crucial component for the maintenance of wakefulness and the suppression of rapid eye movement (REM) sleep. In addition to orexin, melanin-concentrating hormone, and galanin may promote REM sleep. These results suggest that neuropeptides play an important role in sleep–wake regulation. These neuropeptides can be divided into three categories according to their effects on sleep–wake behaviors in rodents and humans. (i) Galanin, melanin-concentrating hormone, and vasoactive intestinal polypeptide are sleep-promoting peptides. It is also noticeable that vasoactive intestinal polypeptide particularly increases REM sleep. (ii) Orexin and neuropeptide S have been shown to induce wakefulness. (iii) Neuropeptide Y and substance P may have a bidirectional function as they can produce both arousal and sleep-inducing effects. This review will introduce the distribution of various neuropeptides in the brain and summarize the roles of different neuropeptides in sleep–wake regulation. We aim to lay the foundation for future studies to uncover the mechanisms that underlie the initiation, maintenance, and end of sleep–wake states.

Sleep State Dependence of Optogenetically evoked Responses in Neuronal Nitric Oxide Synthase-positive Cells of the Cerebral Cortex

Slow-wave activity (SWA) in the electroencephalogram during slow-wave sleep (SWS) varies as a function of sleep-wake history. A putative sleep-active population of neuronal nitric oxide synthase (nNOS)-containing interneurons in the cerebral cortex, defined as such by the expression of Fos in animals euthanized after protracted deep sleep, may be a local regulator of SWA. We investigated whether electrophysiological responses to activation of these cells are consistent with their role of a local regulator of SWA. Using a Cre/loxP strategy, we targeted the population of nNOS interneurons to express the light-activated cation channel Channelrhodopsin2 and the histological marker tdTomato in mice. We then performed histochemical and optogenetic studies in these transgenic mice. Our studies provided histochemical evidence of transgene expression and electrophysiological evidence that the cerebral cortex was responsive to optogenetic manipulation of these cells in both anesthetized and behaving mice. Optogenetic stimulation of the cerebral cortex of animals expressing Channelrhodopsin2 in nNOS interneurons triggered an acute positive deflection of the local field potential that was followed by protracted oscillatory events only during quiet wake and slow wave sleep. The response during wake was maximal when the electroencephalogram (EEG) was in a negative polarization state and abolished when the EEG was in a positive polarization state. Since the polarization state of the EEG is a manifestation of slow-wave oscillations in the activity of underlying pyramidal neurons between the depolarized (LFP negative) and hyperpolarized (LFP positive) states, these data indicate that sleep-active cortical neurons expressing nNOS function in sleep slow-wave physiology.