Effect of arginine vasopressin on acupuncture analgesia in the rat

Effects of acupuncture on hypothalamic-pituitary-adrenal axis: Current status and future perspectives

The hypothalamic-pituitary-adrenal (HPA) axis is a critical component of the neuroendocrine system, playing a central role in regulating the body's stress response and modulating various physiological processes. Dysregulation of HPA axis function disrupts the neuroendocrine equilibrium, resulting in impaired physiological functions. Acupuncture is recognized as a non-pharmacological type of therapy which has been confirmed to play an important role in modulating the HPA axis and thus favorably targets diseases with abnormal activation of the HPA axis. With numerous studies reporting the promising efficacy of acupuncture for neuroendocrine disorders, a comprehensive review in terms of the underlying molecular mechanism for acupuncture, especially in regulating the HPA axis, is currently in need. This review fills the need and summarizes recent breakthroughs, from the basic principles and the pathological changes of HPA axis dysfunction, to the molecular mechanisms by which acupuncture regulates the HPA axis. These mechanisms include the modulation of multiple neurotransmitters and their receptors, neuropeptides and their receptors, and microRNAs in the paraventricular nucleus, hippocampus, amygdala and pituitary gland, which alleviate the hyperfunctioning of the HPA axis. This review comprehensively summarizes the mechanism of acupuncture in regulating HPA axis dysfunction for the first time, providing new targets and prospects for further exploration of acupuncture. Please cite this article as: Zheng JY, Zhu J, Wang Y, Tian ZZ. Effects of acupuncture on hypothalamic-pituitary-adrenal axis: Current status and future perspectives. J Integr Med. 2024; 22(4): 446-459.

A Biophysical Model for Cardiovascular Effects of Acupuncture-Underlying Mechanisms Based on First Principles

According to recent translations by medical professionals of the foundational texts of Chinese Medicine, the acupuncture channel system can be reconciled with the neurovasculature. From there, the underlying mechanisms of the effects of acupuncture can be drawn from established physiology and known physical laws. A large body of research has been carried out using cardiovascular markers to measure the effects of acupuncture. Three of these parameters are re-viewed and explored anew in detail. The focus is on changes in microcirculation, blood pressure, and heart rate variability. The physiological mechanisms accounting for the observed changes are proposed to be ascending vasodilatation, resetting of the baroreceptor reflex, and re-organization of heart beating patterns around intrinsically assigned attractor sets.

Differential role of specific cardiovascular neuropeptides in pain regulation: Relevance to cardiovascular diseases

In many instances, the perception of pain is disproportionate to the strength of the algesic stimulus. Excessive or inadequate pain sensation is frequently observed in cardiovascular diseases, especially in coronary ischemia. The mechanisms responsible for individual differences in the perception of cardiovascular pain are not well recognized. Cardiovascular disorders may provoke pain in multiple ways engaging molecules released locally in the heart due to tissue ischemia, inflammation or cellular stress, and through neurogenic and endocrine mechanisms brought into action by hemodynamic disturbances. Cardiovascular neuropeptides, namely angiotensin II (Ang II), angiotensin-(1-7) [Ang-(1-7)], vasopressin, oxytocin, and orexins belong to this group. Although participation of these peptides in the regulation of circulation and pain has been firmly established, their mutual interaction in the regulation of pain in cardiovascular diseases has not been profoundly analyzed. In the present review we discuss the regulation of the release, and mechanisms of the central and systemic actions of these peptides on the cardiovascular system in the context of their central and peripheral nociceptive (Ang II) and antinociceptive [Ang-(1-7), vasopressin, oxytocin, orexins] properties. We also consider the possibility that they may play a significant role in the modulation of pain in cardiovascular diseases. The rationale for focusing attention on these very compounds was based on the following premises (1) cardiovascular disturbances influence the release of these peptides (2) they regulate vascular tone and cardiac function and can influence the intensity of ischemia - the factor initiating pain signals in the cardiovascular system, (3) they differentially modulate nociception through peripheral and central mechanisms, and their effect strongly depends on specific receptors and site of action. Accordingly, an altered release of these peptides and/or pharmacological blockade of their receptors may have a significant but different impact on individual sensation of pain and comfort of an individual patient.

Intranasal Vasopressin Relieves Orthopedic Pain After Surgery

BACKGROUND

Orthopedic pain after surgery is very common and difficult to manage. Although intranasal arginine vasopressin (AVP) relieves headache (tension-type headache and migraine mostly), the effect of intranasal AVP on the orthopedic pain after surgery is unknown.

AIMS

This study investigated the effect of intranasal AVP on orthopedic pain after surgery in a randomized controlled trial with a double-blind design.

PARTICIPANTS

The study included 653 orthopedic patients and 661 health volunteers.

METHODS

Orthopedic pain was analyzed by the visual analogue scales (VAS) and AVP concentration was determined by radioimmunoassay.

RESULTS

(1) intranasal AVP decreased the VAS level in orthopedic patients 2-4 weeks after surgery in a dose-dependent manner; (2) the cerebrospinal fluid (CSF) AVP concentration in orthopedic patients after surgery was higher than that in the health volunteers (38.57 ± 6.11 pg/mL vs 11.74 ± 2.85 pg/mL, p < .01), but had no change in plasma (p > .05); (3) CSF AVP concentration increased significantly in orthopedic patients during 24 hours after the intranasal AVP (p < .05 or .01), which related with VAS level negatively (all p < .01); (4) during 24 hours, intranasal AVP did not influence not only plasma AVP concentration, but also blood pressure, heart rate, respiratory rate and body temperature in orthopedic patients.

COUCLUSIONS

The findings contribute valuable information that intranasal AVP can treat orthopedic pain after surgery, and AVP could be an option for pain relief by intranasal administration.

Arginine vasopressin improves the memory deficits in Han Chinese patients with first-episode schizophrenia

The memory impairment is a core deficit in the first-episode schizophrenia patients. Arginine vasopressin (AVP) in the brain can improve learning and memory. We performed multicentre, randomized, double-blind, placebo-controlled, parallel-group clinical trial to study the cognitive functioning in Han Chinese first-episode schizophrenic patients in a 12-week treatment regime with the intranasal administration of AVP (128 cases) or placebo (131 cases) in addition to the conventional treatment. The methods of positive and negative syndrome scale (PANSS), Wechsler memory scale-4th edition (WMS-IV) and event-related potential (ERP) were used to study the effects of AVP on the cognitive function. The results showed that (1) AVP concentration decreased in cerebrospinal fluid (CSF) of the right-handed Han Chinese first-episode schizophrenic patients comparing with that of the health volunteers (7.1±1.5pg/ml vs 13.3±1.9pg/ml, p<0.01), and did not change in plasma; (2) AVP significantly improved PANSS scores including total scores, positive symptoms, negative symptoms and general psychopathology comparing with those of the placebo group; (3) AVP elevated WMS-IV scores including the long-term memory (accumulation), short-term memory (recognition, comprehension), immediate memory (number recitation) and memory quotient 4, 8 and 12 weeks after treatment; and (4) AVP did not influence the latency and wave amplitude of target stimulus of P₃₀₀ of right-handed Han Chinese first-episode schizophrenic patients. The data suggested that AVP might improve cognitive process, such as memorizing and extraction of the information although there were many changes of cognitive functions in the right-handed Han Chinese first-episode schizophrenic patients.

Arginine vasopressin relates with spatial learning and memory in a mouse model of spinocerebellar ataxia type 3

Spinocerebellar ataxia is an inherited neurodegenerative disorder that the most prevalent type is type 3 (SCA3). Arginine vasopressin (AVP) is released within the lateral septum for controlling the learning and memory. This communication studied the effect of AVP on the spatial learning and memory of SCA3 mice. The spatial learning and memory were analyzed by Morris water maze test (MWM), and AVP concentration was measured by radioimmunoassay. The results showed that (Alves et al., 2010) the swimming velocity, distance traveled and latency to the platform of MWM in SCA3 mice were reduced slower than those in WT mice over 4 training days (p<0.05, 0.01 or 0.001); (Antunes and Zimmerman, 1978) SCA3 mice showed a lower performance of spatial learning and memory of MWM during the fifth day (test day) compared to WT mice; (Bao et al., 2014) SCA3 mice had a decrease of AVP concentration in cerebral cortex (6.3±0.6pg/mg vs. 11.4±1.0pg/mg, p<0.01), hypothalamus (6.1±1.3ng/mg vs. 10.3±2.1ng/mg, p<0.05), hippocampus (3.2±0.5pg/mg vs. 5.2±1.0pg/mg, p<0.01) and cerebellum (4.7±0.9pg/mg vs. 8.3±1.1pg/mg, p<0.01), not in spinal cord, pituitary and serum; and (Barberies and Tribollet, 1996) intraventricular AVP could significantly quicken swimming velocity, cut down distance traveled and reduce latency to the platform of MWM in a dose-dependent manner, but intraventricular AVP receptor antagonist weakened the spatial learning and memory of MWM in SCA3 mice during the fifth day. The data suggested that AVP in the brain, not spinal cord and peripheral system of SCA3 mice related with the change of the spatial learning and memory of MWM.

The role of arginine vasopressin in electroacupuncture treatment of primary sciatica in human

It has been implicated that electroacupuncture can relieve the symptoms of sciatica with the increase of pain threshold in human, and arginine vasopressin (AVP) in the brain rather than the spinal cord and blood circulation participates in antinociception. Our previous study has proven that AVP in the brain played a role in the process of electroacupuncture analgesia in rat. The goal of the present study was to investigate the role of AVP in electroacupuncture in treating primary sciatica in human. The results showed that (1) AVP concentration of cerebrospinal fluid (CSF) (7.5 ± 2.5 pg/ml), not plasma (13.2 ± 4.2 pg/ml) in primary sciatica patients was lower than that in health volunteers (16.1 ± 3.8 pg/ml and 12.3 ± 3.4 pg/ml), although the osmotic pressure in CSF and plasma did not change; (2) electroacupuncture of the bilateral "Zusanli" points (St. 36) for 60 min relieved the pain sensation in primary sciatica patients; (3) electroacupuncture increased the AVP level of CSF, not plasma in primary sciatica patients; and (4) there was the positive correlation between the effect of electroacupuncture relieving the pain and the AVP level of CSF in the primary sciatica patients. The data suggested that central AVP, not peripheral AVP might improve the effect of electroacupuncture treatment of primary sciatica in human, i.e., central AVP might take part in the electroacupuncture relieving the pain sensation in primary sciatica patients.

Effect of arginine vasopressin on the cortex edema in the ischemic stroke of Mongolian gerbils

Brain edema formation is one of the most important mechanisms of ischemia-evoked cerebral edema. It has been demonstrated that arginine vasopressin (AVP) receptors are involved in the pathophysiology of secondary brain damage after focal cerebral ischemia. In a well-characterized animal model of ischemic stroke of Mongolian gerbils, the present study was undertaken to clear the effect of AVP on cortex edema in cerebral ischemia. The results showed that (1) occluding the left carotid artery of Mongolian gerbils not only decreased the cortex specific gravity (cortex edema) but also increased AVP levels in the ipsilateral cortex (ischemic area) including left prefrontal lobe, left parietal lobe, left temporal lobe, left occipital lobe and left hippocampus for the first 6 hours, and did not change of the cortex specific gravity and AVP concentration in the right cortex (non-ischemic area); (2) there were many negative relationships between the specific gravity and AVP levels in the ischemic cortex; (3) intranasal AVP (50 ng or 200 ng), which could pass through the blood-brain barrier to the brain, aggravated the focal cortex edema, whereas intranasal AVP receptor antagonist-D(CH2)5Tyr(ET)DAVP (2 µg) mitigated the cortex edema in the ischemic area after occluding the left carotid artery of Mongolian gerbils; and (4) either intranasal AVP or AVP receptor antagonist did not evoke that edema in the non-ischemic cortex. The data indicated that AVP participated in the process of ischemia-evoked cortex edema, and the cerebral AVP receptor might serve as an important therapeutic target for the ischemia-evoked cortex edema.

The influence of psychological stress on arginine vasopressin concentration in the human plasma and cerebrospinal fluid

Psychological stress is strain affecting the intangible self, caused by problems in adaptation, perception, and emotions. Previous studies have demonstrated that arginine vasopressin (AVP) plays an important role in psychological stress. The goal of present study was to investigate the interaction between AVP release and cardiovascular functions by measuring AVP concentration and recording blood pressure or heart rate during psychological stress in human. The results showed that (1) psychological stress not only increased the systolic blood pressure, diastolic blood pressure and heart rate, but also elevated the cortisol and AVP concentration in both plasma and CSF in a stress level-dependent manner; (2) there was a positive relationship between plasma AVP concentration and systolic blood pressure, diastolic blood pressure, heart rate or plasma cortisol concentration; (3) there was also a positive relationship between AVP concentrations in plasma and CSF AVP. The data suggested that plasma AVP, which might come from the central nervous system, might influence the cardiovascular functions during psychological stress in human.

Effect of intranasal arginine vasopressin on human headache

Arginine vasopressin (AVP), a nonapeptide hormone of posterior pituitary, reaches the central nervous system from systemic blood circulation with a difficulty because of the blood-brain barrier (BBB). The interest has been expressed in the use of the nasal route for delivery of AVP to the brain directly, exploiting the olfactory pathway. Our previous study has demonstrated that AVP in the brain rather than the spinal cord and blood circulation plays an important role in rat pain modulation. For understanding the role of AVP on pain modulation in human, the communication tried to investigate the effect of intranasal AVP on human headache. The results showed that (1) AVP concentration in both plasma and cerebrospinal fluid (CSF) increased significantly in headache patients, who related with the headache level; (2) there was a positive relationship between plasma and CSF AVP concentration in headache patients; and (3) intranasal AVP could relieve the human headache in a dose-dependent manner. The data suggested that intranasal AVP, which was delivered to the brain through olfactory region, could treat human headache and AVP might be a potential drug of pain relief by intranasal administration.

Oxytocin in the rat caudate nucleus influences pain modulation

Our previous studies have demonstrated that oxytocin (OXT) in the central nervous system plays a role in pain modulation. Many studies have found that caudate nucleus (CdN) enriches OXT and OXT receptors by the methods of historadioautograph and gene expression. The communication was designed to investigate OXT effect in the rat CdN on pain modulation. The results showed that (1) intra-CdN microinjection of OXT receptor antagonist, desGly-NH(2), d(CH(2))(5)[D-Tyr(2), Thr-sup-4]OVT decreased the pain threshold, whereas the local administration of OXT increased the pain threshold in a dose-dependent manner; (2) OXT receptor antagonist can attenuate the analgesic role induced intra-CdN administration of OXT; and (3) pain stimulation could increase OXT concentration in the CdN perfusion liquid. The data suggested that OXT in the CdN was involved in this pain process via OXT receptors.

The effects of single and repeated exposure to 2.45 GHz radiofrequency fields on c-Fos protein expression in the paraventricular nucleus of rat hypothalamus

This study investigated the effects of microwave radiation on the PVN of the hypothalamus, extracted from rat brains. Expression of c-Fos was used to study the pattern of cellular activation in rats exposed once or repeatedly (ten times in 2 weeks) to 2.45 GHz radiation in a GTEM cell. The power intensities used were 3 and 12 W and the Finite Difference Time Domain calculation was used to determine the specific absorption rate (SAR). High SAR triggered an increase of the c-Fos marker 90 min or 24 h after radiation, and low SAR resulted in c-Fos counts higher than in control rats after 24 h. Repeated irradiation at 3 W increased cellular activation of PVN by more than 100% compared to animals subjected to acute irradiation and to repeated non-radiated repeated session control animals. The results suggest that PVN is sensitive to 2.45 GHz microwave radiation at non-thermal SAR levels.

Oxytocin in the periaqueductal gray participates in pain modulation in the rat by influencing endogenous opiate peptides

Periaqueductal gray (PAG) plays a very important role in pain modulation through endogenous opiate peptides including leucine-enkephalin (L-Ek), methionine-enkephalin (M-Ek), β-endorphin (β-Ep) and dynorphin A(1-13) (DynA(1-13)). Our pervious study has demonstrated that intra-PAG injection of oxytocin (OXT) increases the pain threshold, and local administration of OXT receptor antagonist decreases the pain threshold, in which the antinociceptive role of OXT can be reversed by pre-PAG administration of OXT receptor antagonist. The experiment was designed to investigate the effect of OXT on endogenous opiate peptides in the rat PAG during the pain process. The results showed that (1) the concentrations of OXT, L-Ek, M-Ek and β-Ep, not DynA(1-13) in the PAG perfusion liquid were increased after the pain stimulation; (2) the concentrations of L-Ek, M-Ek and β-Ep, not DynA(1-13) in the PAG perfusion liquid were decreased by the OXT receptor antagonist; (3) the increased pain threshold induced by the OXT was attenuated by naloxone, an opiate receptor antagonist; and (4) the concentrations of L-Ek, M-Ek and β-Ep, not DynA(1-13) in the PAG perfusion liquid were increased by exogenous OXT administration. The data suggested that OXT in the PAG could influence the L-Ek, M-Ek and β-Ep rather than DynA(1-13) to participate in pain modulation, i.e. OXT in the PAG participate in pain modulation by influencing the L-Ek, M-Ek and β-Ep rather than DynA(1-13).

Oxytocin in the periaqueductal grey regulates nociception in the rat

Studies have demonstrated that oxytocin (OXT) plays important roles in pain modulation in the central nervous system, and there are OXT receptors in the periaqueductal grey (PAG). The experiment was designed to investigate the effect of OXT in the PAG on antinociception. The results showed that (1) intra-PAG injection of OXT increased the pain threshold, whereas the local administration of the high specific OXT receptor antagonist, desGly-NH(2), d(CH(2))(5)[D-Tyr(2), Thr-sup-4]OVT decreased the pain threshold in a dose-dependent manner; (2) Pain stimulation could elevate OXT concentration in the PAG perfusion liquid. The data suggested that OXT in the PAG was involved in the antinociceptive process through the OXT receptor.

Oxytocin, but not arginine vasopressin is involving in the antinociceptive role of hypothalamic supraoptic nucleus

Our previous study has demonstrated that the hypothalamic supraoptic nucleus (SON) plays a role in pain modulation. Oxytocin (OXT) and arginine vasopressin (AVP) are the important hormones synthesized and secreted by the SON. The experiment was designed to investigate which hormone was relating with the antinociceptive role of the SON in the rat. The results showed that (1) microinjection of L-glutamate sodium into the SON increased OXT and AVP concentrations in the SON perfusion liquid, (2) pain stimulation induces OXT, but not AVP release in the SON, and (3) intraventricular injection (pre-treatment) with OXT antiserum could inhibit the pain threshold increase induced by SON injection of L-glutamate sodium, but administration of AVP antiserum did not influence the antinociceptive role of SON stimulation. The data suggested that the antinociceptive role of the SON relates to OXT rather than AVP.

Endogenous opiates and behavior: 2009

This paper is the 32nd consecutive installment of the annual review of research concerning the endogenous opioid system. It summarizes papers published during 2009 that studied the behavioral effects of molecular, pharmacological and genetic manipulation of opioid peptides, opioid receptors, opioid agonists and opioid antagonists. The particular topics that continue to be covered include the molecular-biochemical effects and neurochemical localization studies of endogenous opioids and their receptors related to behavior (Section 2), and the roles of these opioid peptides and receptors in pain and analgesia (Section 3); stress and social status (Section 4); tolerance and dependence (Section 5); learning and memory (Section 6); eating and drinking (Section 7); alcohol and drugs of abuse (Section 8); sexual activity and hormones, pregnancy, development and endocrinology (Section 9); mental illness and mood (Section 10); seizures and neurologic disorders (Section 11); electrical-related activity and neurophysiology (Section 12); general activity and locomotion (Section 13); gastrointestinal, renal and hepatic functions (Section 14); cardiovascular responses (Section 15); respiration and thermoregulation (Section 16); and immunological responses (Section 17).

Arginine vasopressin induces rat caudate nucleus releasing acetylcholine to participate in pain modulation

A lot of studies have pointed that acetylcholine (Ach), a classic neurotransmitter can regulate pain process in the caudate nucleus (CdN). Our previous report has proven that arginine vasopressin (AVP) effects on pain modulation in the CdN. The communication was designed to investigate the interaction between AVP and Ach in the rat CdN during the pain process. AVP concentration was determined by radioimmunoassay (RIA) and Ach concentration by high performance liquid chromatography (HPLC). The results showed that pain stimulation increased both AVP and Ach concentrations in the CdN perfusion liquid; AVP increased Ach concentration in the CdN perfusion liquid, while AVP receptor antagonist including d(CH(2))(5)Tyr(Me)AVP (V(1) receptor antagonist) and d(CH(2))(5)[D-Ile(2), Ile(4), Ala-NH(2)(9)]AVP (V(2) receptor antagonist) decreased Ach concentration in the CdN perfusion liquid. The data indicated that the analgesic effect of AVP might be involved in the Ach system in the CdN.

Norepinephrine regulates arginine vasopressin secretion in hypothalamic paraventricular nucleus relating with pain modulation

Our previous study has pointed that arginine vasopressin (AVP) and norepinephrine (NA) are two most important bioactive substances that play a role in hypothalamic paraventricular nucleus (PVN) regulating pain process. The communication was designed to investigate the interaction between AVP and NA in the rat PVN during the pain process. We used the potassium iontophoresis inducing tail-flick to test the pain threshold, PVN push-pull perfusion to collect the samples, high performance chromatography (HPLC) to determine the NA concentration and radioimmunoassay (RIA) to measure the AVP concentration. The results showed that (1) pain stimulation increased both NA and AVP concentrations in the PVN perfusion liquid; (2) PVN administration of l-glutamate sodium increased AVP, not NA concentration in the PVN perfusion liquid; (3) AVP or d(CH(2))(5)Tyr(Et)DAVP (AVP-receptor antagonist) neither changed pain threshold, nor influenced NA concentration in the PVN perfusion liquid; (4) Microinjection of NA into PVN could increase pain threshold in a dose-dependent manner, while PVN administration with phentolamine (alpha-receptor antagonist), not propranolol (beta-receptor antagonist) decreased pain threshold; (5) Administration of NA increased AVP concentration, while phentolamine, not propranolol decreased AVP concentration in the PVN perfusion liquid. These data suggested that it is through alpha-receptor rather than beta-receptor, NA induced PVN secretion of AVP that was delivered to the related brain regions to participate in pain modulation.

Arginine vasopressin antinociception in the rat nucleus raphe magnus is involved in the endogenous opiate peptide and serotonin system

Arginine vasopressin (AVP) in the nucleus raphe magnus (NRM) has been implicated in antinociception. This communication was designed to investigate which neuropeptide and neurotransmitter are involved in AVP antinociception in the rat NRM. The results showed that (1) in the NRM perfuse liquid, pain stimulation could increase the concentrations of AVP, leucine-enkephalin (L-Ek), methionine-enkephalin (M-Ek), beta-endorphin (beta-Ep), serotonin (5-HT) and 5-hydroxyindoleacetic acid (5-HIAA), but not change the concentrations of dynorphinA(1-13) (DynA(1-13)), oxytocin, achetylcholine, choline, gamma-aminobutyric acid, glutamate, dopamine, 3,4-dihydroxyphenylacetic acid, homovanilic acid, norepinephrine and epinephrine; (2) in the NRM perfuse liquid, AVP increased the concentrations of L-Ek, M-Ek, beta-Ep, DynA(1-13), 5-HT and 5-HIAA, but did not change the concentrations of oxytocin and the other studied neurotransmitters; (3) AVP antinociception in the NRM was attenuated by cypoheptadine (a 5-HT-receptor antagonist) or naloxone (an opiate receptor antagonist), but was not influenced by the other studied receptor antagonists. The data suggested that AVP antinociception in the NRM might be involved in endogenous opiate peptide and 5-HT system.