[Deep Learning-Based Cardiac Imaging Data Measurement and Its Application in Diagnosis of Sudden Cardiac Death].

ABSTRACT: In the field of forensic medicine, diagnosis of sudden cardiac death is limited by subjective factors and manual measurement methods, so some parameters may have estimation deviation or measurement deviation. As postmortem CT imaging plays a more and more important role in the appraisal of cause of death and cardiopathology research, the application of deep learning such as artificial intelligence technology to analyze vast amounts of cardiac imaging data has provided a possibility for forensic identification and scientific research workers to conduct precise diagnosis and quantitative analysis of cardiac diseases. This article summarizes the main researches on deep learning in the field of cardiac imaging in recent years, and proposes a feasible development direction for the application of deep learning in the virtual anatomy of sudden cardiac death at present.

[A comparative study of retinal nerve fiber layer thickness in AIDS patients with different fundus diseases].

Objective: To investigate the characteristics of retinal nerve fiber layer (RNFL) thickness in AIDS patients with normal fundus, HIV-related microvascular retinopathy (MVR), and cytomegalovirus retinitis (CMVR). Methods: In this cross-sectional study, 111 patients were diagnosed with AIDS from 2012 to 2017 by infectious disease physicians in Beijing You'an Hospital. There were 105 males and 6 females, aged 20-65 years. According to the results of ophthalmic examination, the patients were divided into three groups: 31 patients in the active-stage CMVR group, 47 patients in the MVR group, and 33 patients with normal fundus in the control group. RNFL thickness was measured by optical coherence tomography in all patients. At the same time, visual acuity, intraocular pressure, and fundus were examined, and AIDS-related systemic examination (CD4(+) T lymphocyte count, HAART treatment status, and blood cytomegalovirus DNA level) was performed. The measurement data were compared by t-test, variance analysis or rank sum test. The counting data were compared by chi square test or Fisher exact probability method. Results: In the control group, the thickness of RNFL in the superior quadrant in the left and right eyes was 145 (79, 231) µm and 142 (46, 179) µm, respectively; the difference was statistically significant (Z=-2.481, P=0.013). The RNFL thickness of the diseased and healthy eyes in the MVR group was 116 (91, 138) µm and 122 (82, 192) µm, respectively, with no significant difference (Z=-0.861, P=0.389); the best corrected visual acuity was 0.0 (0.0, 0.2) and 0.0 (0.0, 0.2), respectively, with no significant difference (Z=-0.378, P=0.705). In the CMVR group, the best corrected visual acuity of the diseased and healthy eyes was (0.23±0.48) and (0.02±0.82), respectively, and the difference was statistically significant (t=-2.944, P=0.003); the RNFL thickness was 133 (61, 219) µm and 121 (69, 146), respectively, in the whole optic disc, with statistically significant difference (Z=-2.385, P=0.017), 104 (41, 374) µm and 82 (55, 121) µm, respectively, in the nasal quadrant, and 99 (14, 173) µm and 72 (36, 111) µm, respectively, in the temporal quadrant, with statistically significant difference (Z=-2.045, -2.543; P=0.041, 0.011). The RNFL thickness in the CMVR group, the MVR group, and the control group was 149 (61, 350) µm, 126 (71, 304) µm, and 113 (87, 149) µm, respectively, with statistically significant difference (H=20.908, P=0.000). Conclusions: The fundus of AIDS patients had different characteristics on optical coherence tomography. In active CMVR patients, the thickness of RNFL was generally thickened. In MVR patients, the average thickness of RNFL was thicker than that in the normal control group.(Chin J Ophthalmol, 2020, 56:258-265).

Determination of Electrocution Using Fourier Transform Infrared Microspectroscopy and Machine Learning Algorithm.

ABSTRACT: Objective To analyze the differences among electrical damage, burns and abrasions in pig skin using Fourier transform infrared microspectroscopy （FTIR-MSP） combined with machine learning algorithm, to construct three kinds of skin injury determination models and select characteristic markers of electric injuries, in order to provide a new method for skin electric mark identification. Methods Models of electrical damage, burns and abrasions in pig skin were established. Morphological changes of different injuries were examined using traditional HE staining. The FTIR-MSP was used to detect the epidermal cell spectrum. Principal component method and partial least squares method were used to analyze the injury classification. Linear discriminant and support vector machine were used to construct the classification model, and factor loading was used to select the characteristic markers. Results Compared with the control group, the epidermal cells of the electrical damage group, burn group and abrasion group showed polarization, which was more obvious in the electrical damage group and burn group. Different types of damage was distinguished by principal component and partial least squares method. Linear discriminant and support vector machine models could effectively diagnose different damages. The absorption peaks at 2 923 cm-1, 2 854 cm-1, 1 623 cm-1, and 1 535 cm-1 showed significant differences in different injury groups. The peak intensity of electrical injury's 2 923 cm-1 absorption peak was the highest. Conclusion FTIR-MSP combined with machine learning algorithm provides a new technique to diagnose skin electrical damage and identification electrocution.

[The consistency of ultra-wide-field retinal imaging and the Superfield lens for fundus screening in HIV/AIDS patients].

Objective: To screen the retinopathy in HIV/AIDS patients with both non-mydriatic ultra-wide-field (UWF) retinal imaging and mydriatic fundus examinations with the Superfield lens and a slit lamp biomicroscope, and to evaluate the consistency of two methods and provide reference for future clinical screening work and even technological innovation (such as telemedicine screening and artificial intelligence). Methods: Cross sectional study. One hundred and fifty-eight eyes of 80 HIV-positive patients from the Ophthalmology Department of Beijing Youan Hospital were enrolled in this prospective observational study. All patients underwent comprehensive ophthalmological examination. A single image was obtained from each eye using the UWF fundus imaging system (Daytona, Optos, Dunfermline, UK), and then a dilated fundal examination with the Superfield lens was conducted by another expert. The possible type and location of the lesion with these two methods was recorded respectively. The consistency was compared using the detection rate and Kappa value. Results: Fifty-two patients (65%) had fundus changes, and 28 patients (35%) were normal. Seventy-nine eyes (50%) were normal and 79 eyes (50%) had fundus lesions. Sixty-one eyes (77.2%) had HIV-related fundus lesions, while 18 eyes (22.8%) had non-HIV-related fundus lesions. Fifty-two eyes (65.8%) suffered posterior or posterior involving lesions, and 27 eyes (34.2%) suffered isolated peripheral lesions. The detection rate of UWF retinal imaging and slit lamp biomicroscopy with the Superfield lens was 17.7% (28/158) and 18.4% (29/158) (P=1.000>0.05) for HIV-related microvascular retinopathy, 8.2% and 8.2% (13/158) (χ(2)=158.00, P=1.000) for cytomegalovirus retinitis (CMVR), 36.1% and 36.1% (57/158) (χ(2)=71.066, P=1.000) for HIV-related fundus lesions, 41.8% (66/158) and 47.5% (75/158) (χ(2)=63.514, P=0.136) for fundus lesions, 33.5% (53/158) and 31.0% (49/158) (χ(2)=108.268, P=0.388) for posterior/posterior involving lesions, and 6.4% (10/158) and 16.5% (26/158) (χ(2)=42.001, P=0.000) for isolated peripheral lesions, respectively. In general, the consistency of these two methods was moderate in detecting fundus lesions (Kappa=0.630), HIV-related fundus lesions (Kappa=0.671), HIV-related microvascular retinopathy (Kappa=0.551), and isolated peripheral lesions (Kappa=0.450). According to the fundus location, the two methods showed high consistency in the detection of posterior/posterior involving lesions (Kappa=0.826>0.75) and perfect consistency for CMVR (Kappa=1.0). Conclusions: The UWF retinal imaging system and the Superfield lens showed reasonable consistency in fundus screening in HIV/AIDS patients, especially for CMVR, or lesions in the posterior pole. (Chin J Ophthalmol, 2019, 55:763-768).

Metabolomics Changes of Serum in Rats Dying from Untypical Electric Injury.

ABSTRACT: Objective To study the differential metabolites of serum in rats dying from untypical electric injury by 1H nuclear magnetic resonance （1 NMR）-based metabolomics methods, in order to provide clues for identification of death from antemortem untypical electric injury and instant postmortem electric injury. Methods Models of rats dying from untypical electric injury, instant postmortem electric injury, mechanical asphyxia, mechanical injury, and high temperature injury were established. The rats in control group were executed without any treatment. The serums of rats from every group were detected by 1H NMR-based metabolomics technology to screen differential metabolites. Results The rats dying from untypical electric injury group was compared with those from mechanical asphyxia group, mechanical injury group, high temperature injury group, and control group, respectively. Four chemical shift points with diagnostic value, and their corresponding metabolites were screened. These chemical shift points contained many small molecules, such as alcohols, phenols, sugars, amino acids, etc. The death from untypical electric injury group was compared with those from instant postmortem electric injury group and control group, and then eight chemical shift points with diagnostic value and their corresponding metabolites were screened. These chemical shift points contained small molecules, such as sugars, amino acids, esters, nucleic acids, etc. Conclusion The 1H NMR-based metabolomics technology can identify differential metabolites of serum in rats dying from untypical electric injury, therefore it may provide a basis for the diagnosis of death from untypical electric injury and the identification of antemortem electric injury and instant postmortem electric injury.

Research Progress on Postmortem Changes of Computed Tomography Imaging Characteristics on Corpses.

ABSTRACT: Postmortem changes on corpses appear immediately after death, and can transform the original structure characteristics of the corpse to different degrees as well as show specific changes on computed tomography （CT） images, sometimes with false positives and false negatives, influencing the identification of injuries or diseases. This paper systematically summarizes the postmortem changes of computed tomography imaging characteristics on corpses, to further expand the application of virtopsy in the practices of forensic pathology identification, and provide reference for the identification of injuries, diseases and changes after normal death.

Long non-coding RNA H19 protects acute myocardial infarction through activating autophagy in mice.

OBJECTIVE: We investigate the effect of long non-coding RNA H19 in acute myocardial infarction (AMI) and the underlying mechanism. MATERIALS AND METHODS: C57BL/6 mice were subjected to AMI and injected with lentivirus pcDNA-H19. After AMI procedures for 3 weeks, cardiac function was detected by echocardiography. The infarct size was stained by triphenyltetrazolium chloride. H19 expression in mice was measured by quantitative reverse transcriptase-polymerase chain reaction (qRT-PCR). Protein expressions of LC3, Beclin-1, and ATG-7 in mice were measured by Western blot. RESULTS: Our results indicated that H19 expression was significantly downregulated in the infarcted myocardium. Overexpression of H19 after injection with pcDNA-H19 in mice could reduce infarct size and improve cardiac function through upregulating the ratio of LC3-II/I and expressions of Beclin-1 and ATG-7. CONCLUSIONS: Overexpression of H19 could protect AMI in mice via activating autophagy.

AMPK regulates energy metabolism through the SIRT1 signaling pathway to improve myocardial hypertrophy.

OBJECTIVE: We investigated the correlations of adenosine monophosphate-activated protein kinase (AMPK), Silence information regulator 1 (SIRT1) and energy metabolism with myocardial hypertrophy. MATERIALS AND METHODS: Myocardial hypertrophy experimental model was established via transverse aortic constriction (TAC)-induced myocardial hypertrophy and phenylephrine (PE)-induced hypertrophic myocardial cell culture. After activation of AMPK, the messenger ribonucleic acid (mRNA) expressions in myocardial tissue- and myocardial cell hypertrophy-related genes, atrial natriuretic peptide (ANP) and ß-myosin heavy chain (ß-MHC), were detected. The production rate of 14C-labeled 14CO2 from palmitic acid was quantitatively determined to detect the fatty acid and glucose oxidation of hypertrophic myocardial tissues or cells, and the glucose uptake of myocardial cells was studied using [14C] glucose. Reverse transcription-polymerase chain reaction (RT-PCR) and Western blotting were performed to detect the changes in SIRT1 mRNA and protein expressions in hypertrophic myocardial tissues. Moreover, SIRT1 small interfering ribonucleic acid (siRNA) was used to interfere in SIRT1 expression to further investigate the role of SIRT1 in the effect of AMPK activation on myocardial hypertrophy. RESULTS: AMPK activation could significantly reduce the mRNA expressions of ANP and ß-MHC in vitro and in vivo. AMPK could increase the ejection fraction (EF) and decrease the protein synthesis rate in myocardial cells in mice with myocardial hypertrophy. Besides, AMPK activation could increase the fatty acid oxidation, improve the glucose uptake and reduce the glucose oxidation. After AMPK activation, both SIRT1 mRNA and protein expressions in hypertrophic myocardial tissues and myocardial cells were increased. After SIRT1 siRNA was further used to interfere in SIRT1 expression in myocardial cells, it was found that mRNA expressions and protein synthesis rates of ANP and ß-MHC were increased. CONCLUSIONS: The activation of AMPK can inhibit the myocardial hypertrophy, which may be realized through regulating the myocardial energy metabolism via SIRT1 signaling pathway.

Infrared Spectral Characteristics of Electrical Injuries on Swine Skin Caused by Different Voltages Based on Machine Learning Algorithms.

OBJECTIVES: To explore infrared spectrum characteristics of different voltages induced electrical injuries on swine skin by using Fourier transform infrared-microspectroscopy （FTIR-MSP） combined with machine learning algorithms, thus to provide a reference to the identification of electrical skin injuries caused by different voltages. METHODS: Electrical skin injury model was established on swines. The skin was exposed to 110 V, 220 V and 380 V electric shock for 30 s and then samples were took, with normal skin tissues around the injuries as the control. Combined with the results of continuous section HE staining, the FTIR-MSP spectral data of the corresponding skin tissues were acquired. With the combination of machine learning algorithms such as principal component analysis （PCA） and partial least squares-discriminant analysis （PLS-DA）, different spectral bands were selected （full band 4 000-1 000 cm-1 and sub-bands 4 000-3 600 cm-1, 3 600-2 800 cm-1, 2 800-1 800 cm-1, and 1 800-1 000 cm-1）, and various pretreatment methods were used such as orthogonal signal correction （OSC）, standard normal variables （SNV）, multivariate scatter correction （MSC）, normalization, and smoothing. Thus, the model was optimized, and the classification effects were compared. RESULTS: Compared with simple spectrum analysis, PCA seemed to be better at distinguishing electrical shock groups from the control, but was not able to distinguish different voltages induced groups. PLS-DA based on the 3 600-2 800 cm-1 band was used to identify the different voltages induced skin injuries. The OSC could further optimize the robustness of the 3 600-2 800 cm-1 band model. CONCLUSIONS: It is feasible to identify electrical skin injuries caused by different voltages by using FTIR-MSP technique along with machine learning algorithms.

[Cytokine analysis of aqueous humor in AIDS patients].

Objective: To explore the Cytokine of aqueous humor in AIDS patients with different eye diseases. Methods: A case-control study including 38 patients who was diagnosed as acquired immunodeficiency syndrome(AIDS) at Infectious Center and Department of Ophthalmology in Beijing You'an Hospital, Capital Medical University. And 16 cases of 38 patients were cytomegalovirus retinitis (CMVR), 14 cases were HIV-related retinal disease, and 8 cases presented as normal. A series of tests were performed including vision acuity check, intraocular pressure, fundus photography, blood cell count of CD4+ T lymphocyte and the content of cytokines in aqueous humor by Luminex 200(TM) liquid chip analyzer. Intraocular pressure was analyzed by one-way ANOVA, visual acuity, CD4(+) T lymphocyte count and cytokines were analyzed by Kruskal-Wallis test, the differences between the two groups were compared by Mann-Whitney U test corrected with Bonferroni. Results: Of the 38 AIDS patients [mean age (33.7±10.0) year], 37 were males and 1 was female. The mean visual acuity of 38 patients is logMAR 1.00(0.000, 1.000). The difference of visual acuity among three groups was statistically significant (χ(2)=9.963, P=0.007). The visual acuity in CMVR group was significantly higher than that in HIV-related retinal disease group and AIDS-normal eye group. There was no statistically significant difference of intraocular pressure among three groups (F=0.830, P<0.05). The mean CD4+ T lymphocyte count was 58(4, 550)/µl and the difference was statistically significant among three groups(χ(2)=6.106, P=0.047). The CD4+ T lymphocyte count in AIDS-normal eye group was significantly higher than that in CMVR group and HIV-related retinal disease group. There was no statistically significant difference in CD4+ T lymphocyte count between HIV-related retinal disease group and CMVR group. The following cytokines in CMVR group were significantly higher than the other two groups with statistically significant differences: MIP-1b, IL-6, TNF-α, VEGF, IL-8, MCP-1, IP-10. Conclusions: In patients who was diagnosed as AIDS, cytomegalovirus retinitis would damage vision acuity seriously. The elevated cytokines' level in aqueous humor such as MIP-1b, IL-6, TNF-α, VEGF, IL-8, MCP-1, IP-10, compared with HIV-related retinal disease and AIDS-normal eye cases, may be related to the activity of Th1 cell and monocyte-macrophages system including chemokines, inflammatory factors, and vascular endothelial factors. (Chin J Ophthalmol, 2017, 53: 746-752).

Activation of alpha1 and alpha2 noradrenergic receptors exert opposing effects on excitability of main olfactory bulb granule cells.

The mammalian main olfactory bulb (MOB) receives a dense noradrenergic innervation from the pontine nucleus locus coeruleus that is important for neonatal odor preference learning and odor processing in mature animals. Modulation of GABAergic granule cells (GCs) is thought to play a key role in the net functional impact of norepinephrine (NE) release in the MOB, yet there are few direct studies of the influence of NE on these cells. In the present study we investigated noradrenergic modulation of GC excitability using electrophysiological approaches in rat MOB slices. A moderate concentration of NE (10 microM) and the alpha1 receptor agonist phenylephrine (10 microM) depolarized and increased spontaneous or current injection-evoked spiking in GCs. By contrast, low NE concentrations (0.1-1.0 microM) or the alpha2 receptor agonist clonidine (Clon, 10 microM) hyperpolarized and decreased the discharge of GCs. The effects of NE (10 microM) were blocked by antagonism of alpha1 and alpha2 receptors. Inhibitory effects of low NE concentrations were blocked or converted to excitatory responses by alpha2 receptor blockade, whereas excitatory effects of the moderate NE concentration were converted to inhibitory responses after alpha1 receptor blockade. NE (10 microM) and phenylephrine elicited inward currents that reversed near the potassium equilibrium potential. The effects of NE and phenylephrine were associated with increased membrane input resistance. Clonidine elicited an outward current associated with decreased membrane input resistance that reversed near the potassium equilibrium potential. These results indicate that alpha1 and alpha2 receptor activation exert opposing effects on GC excitability. Low concentrations of NE acting via alpha2 receptors suppress GC excitability, while higher concentrations of NE acting at alpha1 receptors increase GC excitability. These findings are consistent with recent findings that alpha1 and alpha2 receptor activation increase and decrease, respectively, GABAergic inhibition of mitral cells. The differential affinities of alpha1 and alpha2 noradrenergic receptor subtypes may allow for differential modulation of GABA release and olfactory processing as a function of the level of NE release, which in turn, is regulated by behavioral state.

Topography of projections from amygdala to bed nuclei of the stria terminalis.

A collection of 125 PHAL experiments in the rat has been analyzed to characterize the organization of projections from each amygdalar cell group (except the nucleus of the lateral olfactory tract) to the bed nuclei of the stria terminalis, which surround the crossing of the anterior commissure. The results suggest three organizing principles of these connections. First, the central nucleus, and certain other amygdalar cell groups associated with the main olfactory system, innervate preferentially various parts of the lateral and medial halves of the bed nuclear anterior division, and these projections travel via both the stria terminalis and ansa peduncularis (ventral pathway). Second, in contrast, the medial nucleus, and the rest of the amygdalar cell groups associated with the accessory and main olfactory systems innervate preferentially the posterior division, and the medial half of the anterior division, of the bed nuclei. And third, the lateral and anterior basolateral nuclei of the amygdala (associated with the frontotemporal association cortical system) do not project significantly to the bed nuclei. For comparison, inputs to the bed nuclei from the ventral subiculum, infralimbic area, and endopiriform nucleus are also described. The functional significance of these projections is discussed with reference to what is known about the output of the bed nuclei.

Basic organization of projections from the oval and fusiform nuclei of the bed nuclei of the stria terminalis in adult rat brain.

The organization of axonal projections from the oval and fusiform nuclei of the bed nuclei of the stria terminalis (BST) was characterized with the Phaseolus vulgaris-leucoagglutinin (PHAL) anterograde tracing method in adult male rats. Within the BST, the oval nucleus (BSTov) projects very densely to the fusiform nucleus (BSTfu) and also innervates the caudal anterolateral area, anterodorsal area, rhomboid nucleus, and subcommissural zone. Outside the BST, its heaviest inputs are to the caudal substantia innominata and adjacent central amygdalar nucleus, retrorubral area, and lateral parabrachial nucleus. It generates moderate inputs to the caudal nucleus accumbens, parasubthalamic nucleus, and medial and ventrolateral divisions of the periaqueductal gray, and it sends a light input to the anterior parvicellular part of the hypothalamic paraventricular nucleus and nucleus of the solitary tract. The BSTfu displays a much more complex projection pattern. Within the BST, it densely innervates the anterodorsal area, dorsomedial nucleus, and caudal anterolateral area, and it moderately innervates the BSTov, subcommissural zone, and rhomboid nucleus. Outside the BST, the BSTfu provides dense inputs to the nucleus accumbens, caudal substantia innominata and central amygdalar nucleus, thalamic paraventricular nucleus, hypothalamic paraventricular and periventricular nuclei, hypothalamic dorsomedial nucleus, perifornical lateral hypothalamic area, and lateral tegmental nucleus. Moderately dense inputs are found in the parastrial, tuberal, dorsal raphé, and parabrachial nuclei and in the retrorubral area, ventrolateral division of the periaqueductal gray, and pontine central gray. Light projections end in the olfactory tubercle, lateral septal nucleus, posterior basolateral amygdalar nucleus, supramammillary nucleus, and nucleus of the solitary tract. These and other results suggest that the BSTov and BSTfu are basal telencephalic parts of a circuit that coordinates autonomic, neuroendocrine, and ingestive behavioral responses during stress.

Central corticotropin releasing factor (CRF) and adrenergic receptors mediate hemodynamic responses to cocaine.

Cocaine administration evokes cardiovascular responses that are variable in rats such that the pressor response is attributable to either a large increase in systemic vascular resistance and a decrease in cardiac output (vascular responders) or a smaller increase in systemic vascular resistance and no change or an increase in cardiac output (mixed responders). This study was designed to determine the role of central corticotropin releasing factor (CRF) and adrenergic receptors in mediating specific hemodynamic response patterns. Rats were instrumented for ascending aortic blood flow determination (cardiac output) using a pulsed Doppler system, arterial pressure measurement and for intravenous and intracerebroventricular (icv) administration of drugs. After characterizing the hemodynamic response pattern in individual rats to cocaine (5 mg/kg, i.v., 4-6 trials), selective receptor antagonists were administered icv 10 min before cocaine (5 mg/kg, i.v.). Pretreatment with the CRF antagonist alpha-helical CRF(9-41) (10 microg/5 microl, icv) prevented the decrease in cardiac output in vascular responders without altering hemodynamic responses to cocaine in mixed responders. Astressin (5 microg/5 microl, icv) exerted a similar effect in vascular responders. The alpha(2) receptor antagonist, yohimbine (3 microg/microl, icv) also prevented the decrease in cardiac output in vascular responders. Lower doses of alpha-helical CRF(9-41) (1 and 3 microg) were ineffective whereas higher doses of either CRF antagonist were lethal within 24 h. In contrast, propranolol (3 or 30 microg, icv) pretreatment enhanced the cocaine-induced decrease in cardiac output and increase in systemic vascular resistance noted in vascular responders and resulted in a decrease in cardiac output in mixed responders. We conclude that CRF and adrenoceptors in the CNS play an important role in determining the hemodynamic response pattern to cocaine. Furthermore, central beta-adrenoceptors may be responsible for the reported effects of intravenous propranolol on cocaine-induced responses.

Cholecystokinin antisense RNA increases the analgesic effect induced by electroacupuncture or low dose morphine: conversion of low responder rats into high responders.

The analgesic effects of the rat in response to electroacupuncture (EA) or low-dose morphine (3 mg/kg) show marked individual variations. In the midbrain periaqueductal gray (PAG) of the rat, the content of the neuropeptide cholecystokinin octapeptide (CCK-8) was found to be significantly higher in the low responder (LR) rats as compared to that in the high responders (HR). Since PAG has been shown to be a strategic site for CCK-8 to exert an anti-opioid action, a high CCK content in PAG may account for the low analgesic responsiveness to EA and morphine. In order to block the expression of the gene encoding preproCCK in the brain, antisense CCK expression vector pSV2-CCKAS was microinjected into the lateral cerebral ventricle of the rat, leading to a decrease of the CCK-mRNA as well as the CCK-8 content in rat brain. This effect started 4 days after the intracerebroventricular (i.c.v.) injection of the antisense expression vector, and lasted no more than 1 week. This procedure was shown to be very effective in converting LR rats into HR for EA analgesia and morphine analgesia, and also delayed the development of tolerance elicited by prolonged EA stimulation or repeated morphine administration. The time course of the augmentation of opioid analgesia (4-6 days after the i.c.v. injection of the expression vector) paralleled the decrease of the brain CCK-8 content. The results argue that blocking the CCK gene expression in the brain may tilt the balance between opioid and anti-opioid peptides in favor of the former, thus strengthening the EA analgesia and morphine analgesia, and delaying the development of opioid tolerance.