c-Fos expression induced by electroacupuncture at the Zusanli point in rats submitted to repeated immobilization

Acupuncture in the treatment of cocaine addiction: how does it work?

Cocaine is a frequently abused and highly addictive drug that damages brain health and imposes substantial social and economic costs. Acupuncture has been used in the treatment of cocaine addiction and has been shown to improve abnormal mental and motor states. This article mainly focuses on the neurobiological mechanisms involving the central nervous system (CNS) and peripheral nervous system (PNS) that underlie the effects of acupuncture in the treatment of cocaine addiction. The central dopamine system is a key player in acupuncture treatment of cocaine addiction; the ventral tegmental area (VTA)-nucleus accumbens (NAc) signaling pathway, which has a modulatory influence on behavior and psychology after chronic use of cocaine, is a significant target of acupuncture action. Moreover, acupuncture alleviates cocaine-induced seizures or acute psychomotor responses through the paraventricular thalamus and the lateral habenula (LHb)-rostromedial tegmental (RMTg) nucleus circuits. The data suggest that acupuncture can impact various cocaine-induced issues via stimulation of diverse brain areas; nevertheless, the interconnection of these brain regions and the PNS mechanisms involved remain unknown. In this review, we also discuss the effects of specific acupuncture protocols on cocaine addiction and note that variations in needling modalities, current intensities and traditional acupuncture point locations have led to different experimental results. Therefore, standardized acupuncture protocols (with respect to stimulation methods, point locations and number of sessions) may become particularly important in future studies.

Therapeutic Effect and Mechanism of Acupuncture in Autoimmune Diseases

Autoimmune diseases (AIDs) are conditions arising from abnormal immune reactions to autoantigens, which can be defined as the loss of immune tolerance to autoantigens, causing the production of autoantibodies and subsequent inflammation and tissue injury. The etiology of AIDs remains elusive, which may involve both genetic and environmental factors, such as diet, drugs, and infections. Despite rapid progress in the treatment of autoimmune diseases over the past few decades, there is still no approach that can cure AIDs. As an alternative approach, traditional Chinese medicine (TCM) such as acupuncture has been used in an attempt to treat AIDs including multiple sclerosis (MS), rheumatoid arthritis (RA), and inflammatory bowel disease (IBD), and the results have proven to be quite promising, despite the fact that its mechanism is still not fully understood. In this review, the present knowledge regarding mechanisms of acupuncture in the treatment of AIDs has been summarized, and deeper insights will be provided in order to better understand how acupuncture may regulate immune responses during AIDs.

The Modulatory Effect of Acupuncture on the Activity of Locus Coeruleus Neuronal Cells: A Review

The Locus Coeruleus (LC) is a small collection of noradrenergic neurons located in the pons. In the brain, noradrenaline (NE) is primarily produced by noradrenergic cell groups in the LC, which is the largest group of noradrenergic neurons in the central nervous system. Acupuncture, including the electroacupuncture which is a modified acupuncture method, is known to be effective in various kinds of diseases, and the involvement of noradrenergic system in the central nervous system has been reported by previous studies. However, on whether acupuncture can modulate the LC neuronal cells activities, results vary from studies to studies. In this paper, we included twelve articles, which observed the effect of acupuncture on the activities of LC in humans and animals. Our study shows that, among twelve included studies, six reported decrease of LC activities, whereas six showed increase of LC activities after acupuncture treatment. Although it is difficult to draw a firm conclusion, the authors suggest that the difference of frequencies may play an important role in the modulatory effect of acupuncture on LC. Further studies are needed to clarify the precise mechanism of acupuncture on LC, as it can lead to a new therapeutic method for various LC-NE related diseases.

The Expression Patterns of c-Fos and c-Jun Induced by Different Frequencies of Electroacupuncture in the Brain

To investigate patterns of c-Fos and c-Jun expression induced by different frequencies of electroacupuncture (EA) in the brain, goats were stimulated by EA of 0, 2, 60, or 100 Hz at a set of "Baihui, Santai, Ergen, and Sanyangluo" points for 30 min. The pain threshold was measured using the potassium iontophoresis method. The levels of c-Fos and c-Jun were determined with Streptavidin-Biotin Complex immunohistochemistry. The results showed that the pain threshold induced by 60 Hz was 82.2% higher (P < 0.01) than that by 0, 2, or 100 Hz (6.5%, 35.2%, or 40.9%). EA induced increased c-Fos and c-Jun expression in most analgesia-related nuclei and areas in the brain. Sixty Hz EA increased more c-Fos or c-Jun expression than 2 Hz or 100 Hz EA in all the measured nuclei and areas except for the nucleus accumbens, the area septalis lateralis, the caudate nucleus, the nucleus amygdala basalis, and the locus coeruleus, in which c-Fos or c-Jun expressions induced by 60 Hz EA did not differ from those by 2 Hz or 100 Hz EA. It was suggested that 60 Hz EA activated more extensive neural circuits in goats, which may contribute to optimal analgesic effects.

Preemptive Analgesia with Acupuncture Monitored by c-Fos Expression in Rats

Pain behavior and awareness are characterized by heightened alertness and anxiety, which begin to disappear as soon as the curative process starts. The present study aimed to quantify c-fos expression in rat spinal cords and brains after a surgical stimulus and with preoperative or postoperative acupuncture. Animals were randomly divided into preoperative and postoperative groups and were then further divided into control, manual acupuncture (MA), or electroacupuncture (EA) groups. Expression of c-fos was quantified using immunohistochemistry. The collected data were analyzed using the t test at a 5% probability level. Presurgery and postsurgery spinal cord c-fos expressions were similar in all of the treatment groups. In the control rats, c-fos expression was higher before surgery than after surgery, contradicting the expected outcome of acupuncture and preemptive analgesia. After treatment, the expression of c-fos in the brains of the rats in the MA and the EA groups was reduced compared with that of the rats in the control group. These findings suggest that acupuncture used as preemptive analgesia in rats is a useful model for studying its application in human treatment.

Acupuncture Affects Autonomic and Endocrine but Not Behavioural Responses Induced by Startle in Horses

Startle is a fast response elicited by sudden acoustic, tactile, or visual stimuli in a variety of animals and in humans. As the magnitude of startle response can be modulated by external and internal variables, it can be a useful tool to study reaction to stress. Our study evaluated whether acupuncture can change cardiac autonomic modulation (heart rate variability); and behavioural (reactivity) and endocrine (cortisol levels) parameters in response to startle. Brazilian Sport horses (n = 6) were subjected to a model of startle in which an umbrella was abruptly opened near the horse. Before startle, the horses were subjected to a 20-minute session of acupuncture in acupoints GV1, HT7, GV20, and BL52 (ACUP) and in nonpoints (NP) or left undisturbed (CTL). For analysis of the heart rate variability, ultrashort-term (64 s) heart rate series were interpolated (4 Hz) and divided into 256-point segments and the spectra integrated into low (LF; 0.01–0.07 Hz; index of sympathetic modulation) and high (HF; 0.07–0.50 Hz; index of parasympathetic modulation) frequency bands. Acupuncture (ACUP) changed the sympathovagal balance with a shift towards parasympathetic modulation, reducing the prompt startle-induced increase in LF/HF and reducing cortisol levels 30 min after startle. However, acupuncture elicited no changes in behavioural parameters.

The pattern of c-Fos expression and its refractory period in the brain of rats and monkeys

Intense activation of neurons triggers the appearance of immediate expression genes, including c-Fos. This gene is related to various signal cascades involved in biochemical processes such as neuronal plasticity, cell growth and mitosis. Here we investigate the expression pattern and the refractory period of c-Fos in rats and monkey's brains after stimulation with pentylenetetrazol. Rats and monkeys were sacrificed at various times after PTZ-induced seizure. Here we show that rats and monkeys already showed c-Fos expression at 0.5 h after seizure. Yet, the pattern of protein expression was longer in monkeys than rats, and also was not uniform (relative intensity) across different brain regions in monkeys as opposed to rats. In addition monkeys had a regional brain variation with regard to the temporal profile of c-Fos expression, which was not seen in rats. The refractory period after a second PTZ stimulation was also markedly different between rats and monkeys with the latter even showing a summatory effect on c-Fos expression after a second stimulation. However, assessment of c-Fos mRNA in rats indicated a post-transcriptional control mechanism underlying the duration of the refractory period. The difference in the protein expression pattern in rodents and primates characterizes a functional aspect of brain biochemistry that differs between these mammalian orders and may contribute for the more developed primate cognitive complexity as compared to rodents given c-Fos involvement in cognitive and learning tasks.

Electroacupuncture reduces cocaine-induced seizures and mortality in mice

The aims of this study were to characterize the protective profile of electroacupuncture (EA) on cocaine-induced seizures and mortality in mice. Mice were treated with EA (2 Hz, 50 Hz, and 100 Hz), or they underwent needle insertion without anesthesia at the Dazhui (GV14) and Baihui (GV20) acupoints before cocaine administration. EA at 50 Hz applied to GV14 and GV20 significantly reduced the seizure severity induced by a single dose of cocaine (75 mg/kg; i.p.). Furthermore, needle insertion into GV14 and GV20 and EA at 2 Hz and 50 Hz at both acupoints significantly reduced the mortality rate induced by a single lethal dose of cocaine (125 mg/kg; i.p.). In the sham control group, EA at 50 Hz applied to bilateral Tianzong (SI11) acupoints had no protective effects against cocaine. In addition, EA at 50 Hz applied to GV14 and GV20 failed to reduce the incidence of seizures and mortality induced by the local anesthetic procaine. In an immunohistochemistry study, EA (50 Hz) pretreatment at GV14 and GV20 decreased cocaine (75 mg/kg; i.p.)-induced c-Fos expression in the paraventricular thalamus. While the dopamine D₃ receptor antagonist, SB-277011-A (30 mg/kg; s.c), did not by itself affect cocaine-induced seizure severity, it prevented the effects of EA on cocaine-induced seizures. These results suggest that EA alleviates cocaine-induced seizures and mortality and that the dopamine D₃ receptor is involved, at least in part, in the anticonvulsant effects of EA in mice.

ST36 laser acupuncture reduces pain-related behavior in rats: involvement of the opioidergic and serotonergic systems

Laser acupuncture is a modality of low-level light therapy used as an alternative to needling for the past three decades. Although it has proved effective for the treatment of various conditions, the mechanisms underlying its effects are not fully understood. To contribute to this understanding, this study was designed to (1) evaluate the antinociceptive effect of ST36 laser acupuncture (830 nm, 3 J/cm(2)) in rat models of acute nociception and (2) to investigate the opioidergic and serotonergic systems involvement in this effect. Our results demonstrate that ST36 laser acupuncture inhibited (36 ± 2 %) acetic acid-induced abdominal constrictions and both neurogenic (48 ± 7 %) and inflammatory (phase IIA 42 ± 8 % and phase IIB 83 ± 6 %) phases of formalin-induced nociceptive behavior. Moreover, the antinociceptive activity of laser irradiation in the acetic acid test was significantly reversed by preadministration of naloxone (1 mg/kg, nonselective opioid receptor antagonist), pindolol (1 mg/kg, subcutaneous; nonselective 5-HT 1A/B receptor antagonist), and ketanserin (1 mg/kg; selective 5-HT2A receptor antagonist) but not by ondansetron (1 mg/kg, selective 5-HT3 receptor antagonist). Taken together, our data demonstrate, for the first time, that (1) ST36 laser acupuncture elicited significant antinociceptive effect against acetic acid- and formalin-induced behavior in rats and that (2) this effect is mediated by activation of the opioidergic and serotonergic (5-HT1 and 5-HT2A receptors) systems.

High-frequency electroacupuncture versus carprofen in an incisional pain model in rats

The objective of the present study was to compare the effect of electroacupuncture (EA) and carprofen (CP) on postoperative incisional pain using the plantar incision (PI) model in rats. A 1-cm longitudinal incision was made through skin, fascia and muscles of a hind paw of male Wistar rats and the development of mechanical and thermal hypersensitivity was determined over 4 days using the von Frey and Hargreaves methods, respectively. Based on the experimental treatments received on the third postoperative day, the animals were divided into the following groups: PI+CP (CP, 2 mg/kg, po); PI+EAST36 (100-Hz EA applied bilaterally at the Zusanli point (ST36)); PI+EANP (EA applied to a non-acupoint region); PI+IMMO (immobilization only); PI (vehicle). In the von Frey test, the PI+EAST36 group had higher withdrawal force thresholds in response to mechanical stimuli than the PI, PI+IMMO and PI+EANP groups at several times studied. Furthermore, the PI+EAST36 group showed paw withdrawal thresholds in response to mechanical stimuli that were similar to those of the PI+CP group. In the Hargreaves test, all groups had latencies higher than those observed with PI. The PI+EAST36 group was similar to the PI+IMMO, PI+EANP and PI+CP groups. We conclude that 100-Hz EA at the ST36 point, but not at non-acupoints, can reduce mechanical nociception in the rat model of incisional pain, and its effectiveness is comparable to that of carprofen.

Electroacupuncture increases the concentration and organization of collagen in a tendon healing model in rats

The aim of this study was to investigate the effect of electroacupuncture (EA) on the composition and organization of the extracellular matrix of the rat Achilles tendon after a partial transection during the proliferative phase of healing. Wistar rats were divided into three groups: rats that were not tenotomized (G1), tenotomized rats (G2), and rats that were tenotomized and submitted to EA (G3). EA was applied 15 days after injury at the ST36 and BL57 acupoints for 20 min, three times per week on alternate days for a total of six sessions. Biochemical analyses were performed using non-collagenous proteins, glycosaminoglycans, and hydroxyproline quantifications. An analysis of metalloproteinase-2 was carried out by zymography. The general organization of the extracellular matrix and the metachromasy of the tendons were analyzed under light microscopy. The organization of the bundles of collagen fibers was analyzed by birefringence analysis. The results showed that EA did not alter the concentration of non-collagenous proteins or glycosaminoglycans or the enzymatic activity of metalloproteinase-2 in the transected tendons. However, the concentration of hydroxyproline was significantly increased when these tendons were treated by EA. The analysis of birefringence showed a higher organization of collagen fibers in the group treated by EA. These results indicate, for the first time, that EA may offer therapeutic benefits for the treatment of tendon injuries by increasing the concentration of collagen and by inducing a better molecular organization of the collagen fibers, which may improve the mechanical strength of the tendon after injury.

Neural acupuncture unit: a new concept for interpreting effects and mechanisms of acupuncture

When an acupuncture needle is inserted into a designated point on the body and mechanical or electrical stimulation is delivered, various neural and neuroactive components are activated. The collection of the activated neural and neuroactive components distributed in the skin, muscle, and connective tissues surrounding the inserted needle is defined as a neural acupuncture unit (NAU). The traditionally defined acupoints represent an anatomical landmark system that indicates local sites where NAUs may contain relatively dense and concentrated neural and neuroactive components, upon which acupuncture stimulation would elicit a more efficient therapeutic response. The NAU-based local mechanisms of biochemical and biophysical reactions play an important role in acupuncture-induced analgesia. Different properties of NAUs are associated with different components of needling sensation. There exist several central pathways to convey NAU-induced acupuncture signals, Electroacupuncture (EA) frequency-specific neurochemical effects are related to different peripheral and central pathways transmitting afferent signals from different frequency of NAU stimulation. More widespread and intense neuroimaging responses of brain regions to acupuncture may be a consequence of more efficient NAU stimulation modes. The introduction of the conception of NAU provides a new theoretical approach to interpreting effects and mechanisms of acupuncture in modern biomedical knowledge framework.

Involvement of Interleukin-10 in the Anti-Inflammatory Effect of Sanyinjiao (SP6) Acupuncture in a Mouse Model of Peritonitis

In this study, we determined the anti-inflammatory effect of manual acupuncture at the Sanyinjiao or Spleen 6 (SP6) point on carrageenan-induced peritonitis in mice and investigated mechanisms that may underlie this effect. In the first set of experiments, male Swiss mice were allocated into five groups: the control (sterile saline), dexamethasone (DEXA), invasive sham-acupuncture (non-acupoint), SP6 acupuncture and carrageenan-treated groups. Ten minutes after needle retention or 30 min after DEXA treatment, mice received an intraperitoneal injection of carrageenan (750 μg/mouse). After 4 h, total leukocyte and differential cell counts (neutrophils and mononuclear), myeloperoxidase (MPO) activity, vascular permeability and cytokine levels were evaluated. In another set of experiments, adrenalectomized (ADX) mice were used to study the involvement of the adrenal gland on the therapeutic effects of acupuncture. Mice were allocated into two groups: the ADX and sham-operated animals (Sham ADX) that were subdivided into four subgroups each: the control (sterile saline), DEXA, SP6 acupuncture and carrageenan-treated groups. The SP6 and DEXA treatments inhibited the inflammatory cell infiltration, vascular permeability and MPO activity in carrageenan-injected mice. In addition, the SP6 treatment also increased interleukin (IL)-10 levels. In contrast, when the animals were adrenalectomized, the SP6 treatment failed to reduce total leukocyte and the plasma extravasation. In conclusion, this study clearly demonstrates the anti-inflammatory effect of SP6 acupuncture in a model of carrageenan-induced peritonitis. Our results demonstrated that SP6 acupuncture depends of the adrenal glands and increased IL-10 levels to produce its anti-inflammatory action.

Catecholaminergic systems in stress: structural and molecular genetic approaches

Stressful stimuli evoke complex endocrine, autonomic, and behavioral responses that are extremely variable and specific depending on the type and nature of the stressors. We first provide a short overview of physiology, biochemistry, and molecular genetics of sympatho-adrenomedullary, sympatho-neural, and brain catecholaminergic systems. Important processes of catecholamine biosynthesis, storage, release, secretion, uptake, reuptake, degradation, and transporters in acutely or chronically stressed organisms are described. We emphasize the structural variability of catecholamine systems and the molecular genetics of enzymes involved in biosynthesis and degradation of catecholamines and transporters. Characterization of enzyme gene promoters, transcriptional and posttranscriptional mechanisms, transcription factors, gene expression and protein translation, as well as different phases of stress-activated transcription and quantitative determination of mRNA levels in stressed organisms are discussed. Data from catecholamine enzyme gene knockout mice are shown. Interaction of catecholaminergic systems with other neurotransmitter and hormonal systems are discussed. We describe the effects of homotypic and heterotypic stressors, adaptation and maladaptation of the organism, and the specificity of stressors (physical, emotional, metabolic, etc.) on activation of catecholaminergic systems at all levels from plasma catecholamines to gene expression of catecholamine enzymes. We also discuss cross-adaptation and the effect of novel heterotypic stressors on organisms adapted to long-term monotypic stressors. The extra-adrenal nonneuronal adrenergic system is described. Stress-related central neuronal regulatory circuits and central organization of responses to various stressors are presented with selected examples of regulatory molecular mechanisms. Data summarized here indicate that catecholaminergic systems are activated in different ways following exposure to distinct stressful stimuli.

Persistent inflammatory pain decreases the antinociceptive effects of the mu opioid receptor agonist DAMGO in the locus coeruleus of male rats

Persistent inflammatory nociception increases levels of endogenous opioids with affinity for delta opioid receptors in the ventromedial medulla and enhances the antinociceptive effects of the mu opioid receptor (MOPr) agonist [D-Ala2, N-Me-Phe4, Gly5-ol]enkephalin (DAMGO) [Hurley, R.W., Hammond, D.L., 2001. Contribution of endogenous enkephalins to the enhanced analgesic effects of supraspinal mu opioid receptor agonists after inflammatory injury. J. Neurosci. 21, 2536-2545]. It also increases levels of endogenous opioids that act at MOPr elsewhere in the CNS [Zangen, A., Herzberg, U., Vogel, Z., Yadid, G., 1998. Nociceptive stimulus induces release of endogenous beta-endorphin in the rat brain. Neuroscience 85, 659-662]. This study tested the hypothesis that a sustained release of endogenous opioids leads to a downregulation of MOPr in the locus coeruleus (LC) and induces a state of endogenous opioid tolerance. Four days after injection of complete Freund's adjuvant (CFA) in the left hindpaw of the rat, both the magnitude and duration of the antinociception produced by microinjection of DAMGO in the right LC were reduced. Saturation isotherms demonstrated a 50% decrease in MOPr B(max) in homogenates of the LC from CFA-treated rats; K(d) was unchanged. Receptor autoradiography revealed that this decrease was bilateral. The decreased efficacy of DAMGO in CFA-treated rats most likely results from a decreased number of MOPr in the LC. Microinjection of the MOPr antagonist D-Phe-Cys-Tyr-D-Trp-Arg-Thr-Pen-Thr-NH2 (CTAP) in the LC did not exacerbate hyperalgesia in the ipsilateral hindpaw or produce hyperalgesia in the contralateral hindpaw of CFA-treated rats. The downregulation in MOPr is therefore unlikely to result from the induction of endogenous opioid tolerance in the LC. These results indicate that persistent inflammatory nociception alters the antinociceptive actions of MOPr agonists in the CNS by diverse mechanisms that are nucleus specific and likely to have different physiological implications.

Opioidergic orofacial antinociception induced by electroacupuncture at acupoint St36

The participation of opioids in the antinociceptive effect of electroacupuncture was evaluated in terms of nociception produced by thermal stimuli applied to the face of male Wistar rats, weighing 180-230 g. Electrical stimulation (bipolar and asymmetric square wave with 0.5 mA intensity for 20 min) of acupoint St36, located in the anterior tibial muscle 10 mm distal to the knee joint, induced antinociception in the present model, which was maintained for 150 min. Acupoint LI4, located in the junction of the first and second metacarpal bones, did not achieve antinociception at any frequency studied (5 Hz: 1.7 +/- 0.1; 30 Hz: 1.8 +/- 0.1; 100 Hz: 1.7 +/- 0.1 vs 1.4 +/- 0.2). The antinociception obtained by stimulation of acupoint St36 was only achieved when high frequency 100 Hz (3.0 +/- 0.2 vs 1.0 +/- 0.1) was used, and not with 5 or 30 Hz (1.2 +/- 0.2 and 0.7 +/- 0.1 vs 1.0 +/- 0.1). The antinociceptive effect of acupuncture occurred by opioid pathway activation, since naloxone (1 and 2 mg/kg, subcutaneously) antagonized it (1.8 +/- 0.2 and 1.7 +/- 0.2 vs 3.0 +/- 0.1).

Nitric oxide/cGMP pathway mediates orofacial antinociception induced by electroacupuncture at the St36 acupoint

The aim of the present study was to test the hypothesis that electroacupuncture (EA) at acupoint St36 induces antinociception by activation of the L-arg/NO/cGMP pathway. Nociception was produced by thermal stimuli applied to the face of Wistar rats and latency was measured by face withdrawal. Electric stimulation of acupoint St36 for 20 min induced antinociception in this model, which was maintained for 150 min. For comparison, a so-called dry needle group (DN) was used, which received needling at the same point without stimulation. The antinociception obtained by stimulation of acupoint St36 was only achieved when high frequency (100 Hz) was used, whereas low frequencies (5 and 30 Hz) were not capable of achieving this effect. Subcutaneous administration of both inhibitors of NO synthase (N-nitro-L-arginine) and guanylyl cyclase (ODQ) and intraperitoneal administration of specific antagonists of neuronal NO synthase (L-NNA) and inductible NO synthase (aminoguanidine) antagonized the antinociception induced by St36 stimulation. The results of this paper suggest that stimulation of acupoint St36 at high frequency induces antinociception, which seems to be related to L-arg/NO/cGMP pathway activation.

Antidepressive-like effects of electroacupuncture in rats

Here, we investigate the effects of electroacupunture on the depressive-like symptoms in learned helplessness and forced swim tests in rats. Electroacupuncture stimulation (EA) was provided at ST-36 (Zusanli) and SP-6 (Sanyinjiao) acupoints. A positive control group was treated with imipramine. To verify the effects of EA over serotonergic system, other additional groups received daily, for three days, p-chlorophenylalanine and after two days, were submitted to behavioral tests. EA, like imipramine, enhanced the successful active avoidance in the learned helplessness and diminished the time spent in immobility position in the forced swim test, without affecting the number of squares crossed in the open field test. The administration of p-chlorophenylalanine abolished the antidepressive-like effect of EA. EA generates a clear antidepressant effect in two different animal models of depression, and this effect is related, at least in part, to the serotonergic system.

Effect of acupuncture on pubertal development of rats and rabbits at different developmental stages

Physiological and endocrine studies on sexual development in animals and effects of acupuncture on sexual development are limited. Therefore, we investigated the effect of electro-acupuncture (EA) on the arcuate nucleus (Arc) and release of gonadotropin-releasing hormone (GnRH) in animals at different developmental stages. In Experiment 1, EA stimulation (30 Hz) was performed for 30 min per day in EA group of rabbits for 48 days, while the control group (mature rabbits) was not given EA. Arc discharges in those two groups were measured after the 48-day treatment. Arc discharge was also measured in the pre-pubertal group (as control) without EA treatment. Then, all three groups were treated with transient EA for 30 min and Arc discharges were determined again. In Experiment 2, EA (3 Hz) at the same acupoints or non-acupoints as that in the rabbits was performed for 20 min per day in different developmental group of Sprague-Dawley rats for 10 days. GnRH mRNA expression in the hypothalamus of rats was determined using RT-PCR and real-time PCR. The serum sexual hormone, sperm count, and body weight was measured. The results showed that the Arc discharge (P<0.01), testosterone (T) (P<0.01) and sperm count (P<0.01) in male rabbits were reduced by repeated EA. However, the body weight of rabbits was not changed after EA compared to the control in Experiment 1. In Experiment 2, GnRH mRNA expression in rats of the early pubertal group (EPG) and adult group (AG) were significantly depressed after repeated EA at acupoints (P<0.01). The sexual hormones were negatively influenced by repeated EA during puberty. Sperm count was reduced significantly after repeated EA at time of puberty (P<0.01). Repeated EA did not influence body weight of rats (P>0.01) and structures of the gonadial tissues during development. The results suggested that repeated EA is a good option that can be considered for regulating the function of the hypothalamus-pituitary-gonad (HPG) axis during puberty.

Electroacupuncture at ST-36 accelerates colonic motility and transit in freely moving conscious rats

Acupuncture is useful for functional bowel diseases, such as constipation and diarrhea. However, the mechanisms of beneficial effects of acupuncture on colonic function have scarcely ever been investigated. We tested the hypothesis that electroacupuncture (EA) at ST-36 stimulates colonic motility and transit via a parasympathetic pathway in conscious rats. Hook-shaped needles were inserted at bilateral ST-36 (lower limb) or BL-21 (back) and electrically stimulated at 10 Hz for 20 min. We also studied c-Fos expression in response to EA at ST-36 in Barrington's nucleus of the pons. EA at ST-36, but not BL-21, significantly increased the amplitude of motility at the distal colon. The calculated motility index of the distal colon increased to 132 +/- 9.9% of basal levels (n = 14, P < 0.05). In contrast, EA at ST-36 had no stimulatory effects in the proximal colon. EA at ST-36 significantly accelerated colonic transit [geometric center (GC) = 6.76 +/- 0.42, n = 9, P < 0.001] compared with EA at BL-21 (GC = 5.23 +/- 0.39, n = 7). The stimulatory effect of EA at ST-36 on colonic motility and transit was abolished by pretreatment with atropine. EA-induced acceleration of colonic transit was also abolished by extrinsic nerve denervation of the distal colon (GC = 4.69 +/- 0.33, n = 6). The number of c-Fos-immunopositive cells at Barrington's nucleus significantly increased in response to EA at ST-36 to 8.1 +/- 1.1 cells/section compared with that of controls (2.4 +/- 0.5 cells/section, n = 3, P < 0.01). It is concluded that EA at ST-36 stimulates distal colonic motility and accelerates colonic transit via a sacral parasympathetic efferent pathway (pelvic nerve). Barrington's nucleus plays an important role in mediating EA-induced distal colonic motility in conscious rats.

Single and repeated immobilization stress differentially trigger induction and phosphorylation of several transcription factors and mitogen-activated protein kinases in the rat locus coeruleus

The locus coeruleus (LC) is a critical stress-responsive location that mediates many of the responses to stress. We used immunoblotting and immunohistochemistry to investigate changes in induction and phosphorylation of several transcription factors and kinases in the LC that may mediate the stress-triggered induction of tyrosine hydroxylase (TH) transcription. Rats were exposed to single or repeated immobilization stress (IMO) for brief (5 min), intermediate (30 min) or sustained (2 h) duration. Single IMO elicited rapid induction of c-Fos and phosphorylation of cyclic AMP response element-binding protein (CREB) without changing the expression of early growth response (Egr)1, Fos-related antigen (Fra)-2 or phosphorylated activating transcription factor-2. Repeated IMO triggered increased phosphorylation and levels of CREB along with transient induction of c-Fos and increased Fra-2 expression. Several mitogen-activated protein kinases were activated by repeated IMO, shown by increased phosphorylation of p38, c-Jun N-terminal kinase (JNK)1/2/3 and extracellular signal-regulated kinase (ERK1/2). ERK1 was the major isoform expressed, and ERK2 the predominant isoform phosphorylated. Repeated IMO elicited hyperphosphorylation of ERK1/2 selectively in TH immunoreactive neurons, with substantial nuclear localization. These distinct alterations in transcriptional pathways following repeated compared with single stress may be involved in mediating long-lasting neuronal remodeling and are implicated in the mechanisms by which acute beneficial responses to stress are converted into prolonged adaptive or maladaptive responses.

Stress-induced c-Fos expression is differentially modulated by dexamethasone, diazepam and imipramine

Immobilization stress upregulates c-Fos expression in several CNS areas. Repeated stress or the use of drugs can modulate stress-induced c-Fos expression. Here, we investigated in 40 different areas of the rat brain the effects of dexamethasone (SDX, a synthetic glucocorticoid), diazepam (SBDZ, a benzodiazepine), and imipramine (IMI, an antidepressant) on the c-Fos expression induced by restraint stress. Wistar rats were divided into four groups and submitted to 20 days of daily injection of saline (three first groups) or imipramine, 15 mg/kg, i.p. On day 21, animals were submitted to injections of saline (somatosensory, SS), SDX (1 mg/kg, i.p.), SBDZ (5 mg/kg, i.p.), or IMI (15 mg/kg, i.p.) before being submitted to restraint. Immediately after stress, the animals were perfused and their brains processed with immunohistochemistry for c-Fos (Ab-5 Oncogene Science). Dexamethasone reduced stress-induced c-Fos expression in SS cortex, hippocampus, paraventricular nucleus of the hypothalamus (PVH), and locus coeruleus (LC), whereas diazepam reduced c-Fos staining in the SS cortex, hippocampus, bed nucleus of stria terminalis, septal area, and hypothalamus (preoptic area and supramammillary nucleus). Chronic administration of imipramine decreased staining in the hippocampus, PVH, and LC, while increasing it in the nucleus raphe pallidus. We conclude that dexamethasone, diazepam and imipramine differentially modulate stress-induced Fos expression. The present study provides an important comparative background that may help in the further understanding of the effects of these compounds and on the brain activation as well as on the behavioral, neuroendocrine, and autonomic responses to stress.