Molecular genetic evidence for different clonal origin of components of human renal angiomyolipomas

Renal angiomyolipoma is a benign neoplasm composed of variable proportions of blood vessels, smooth muscle, and adipose tissue. Smooth muscle, adipose tissue, blood vessels, and adjacent normal kidney tissue were separately microdissected from sections prepared from formalin-fixed, paraffin-processed tissues from angiomyolipomas from 18 women. X chromosome inactivation analysis using the methylation pattern at exon 1 of the human androgen receptor gene on chromosome Xq11-12 was used to study the clonal origin of each component. Nonrandom inactivation of X chromosomes was found in six of the 15 informative tumors. The smooth muscle and adipose tissue showed differing patterns of nonrandom inactivation of X chromosomes in five angiomyolipomas and the same pattern of nonrandom inactivation of X chromosomes in one. Samples from the blood vessels showed random inactivation of X chromosomes in all informative cases. Our data showed that the adipose tissue and smooth muscle cells of renal angiomyolipoma are both monoclonal but may arise independently. The coexistence of tumor subclones with morphologic heterogeneity can lead to the formation of a clinically detectable tumor.

Predicting cancer progression in patients with penile squamous cell carcinoma: the importance of depth of invasion and vascular invasion

The ability to predict cancer progression may help the clinical management of patients with penile squamous cell carcinoma. We studied 22 cases of squamous cell carcinoma of the penis diagnosed between 1989 and 1998. The depth of invasion was measured from the basement membrane of the squamous epithelium to the deepest invasive cancer cells. Cancer progression was defined as the development of lymph node metastasis or distant metastasis. The mean patient age was 63 years and the mean follow-up was 28 months. Ten patients developed cancer progression. The mean depth of invasion among patients with cancer progression was 9.8 mM, as compared to the mean depth of invasion of 4.0 mM among those patients without cancer progression (P =.02). Vascular invasion was also predictive of cancer progression (P =.02). Metastases developed in the majority (6 out of 7) of cases invading more than 6 mM, but developed only in a minority (4 out of 15) of cases invading 6 mM or less. We conclude that depth of invasion and vascular invasion are significant predictors of cancer progression for penile squamous cell carcinoma.

Improved islet survival and in vitro function using solubilized small intestinal submucosa

In vitro proliferation of isolated pancreatic islets has become an area of great interest given the scarcity of clinical islet donors and the islet mass requirements for clinical islet transplantation. Small intestinal submucosa (SIS), a naturally occurring extracellular matrix, has been investigated to promote wound healing, tissue remodeling and cell growth. This study evaluated recovery and function of isolated canine pancreatic islets following in vitro tissue culture. Pancreatic islets were isolated from mongrel dogs using standard surgical procurement followed by intraductal collagenase distension, mechanical dissociation and EuroFicoll purification. Groups of purified islets were cultured in a humidified atmosphere of 95% air and 5% CO(2) for 48 hours in standard islet culture conditions of CMRL 1066 tissue culture media (Gibco) which had been supplemented with 25microM HEPES, penicillin/streptomycin and either 10% heat inactivated fetal calf serum (FCS, Gibco) or solubilized SIS solution (Cook Biotech, Inc., West Lafayette, IN). The mean recovery of islets following the culture period was determined by sizing duplicate counts of a known volume and viability was assessed by static incubation with low glucose (2.8 mM), high glucose (20 mM) and high glucose solution supplemented with 50 microm IBMX solution. Remaining islets were embedded histologically. From a consecutive series of six culture experiments, a significantly higher (p < 0.05) recovery of islets co-cultured with SIS was observed when compared to controls. Mean islet recovery was 84.5 +/- 2.9% (mean +/- SEM) from the SIS cultured group compared with 64.7 +/- 4.5% from the control group cultured in FCS (p < 0.05, n=6). Islets from the SIS treated group exhibited a significantly higher (p <, 0.05) insulin response to the high glucose stimulus than islets cultured in the standard FCS cultured solution. The calculated stimulation index was 12.3 +/- 3.4 for the SIS-treated group compared with 5.6 +/- 1.8 for the standard cultured group (p < 0.05). The overall mean numbers of islets recovered following in vitro culture was also higher in the SIS-treated group. The proportion of islets with a mean diameter >150 microm increased from 24% to 31% in the SIS-treated group, whereas the same proportion decreased to 18% from 22% in the control (FCS-treated) group. Histological evaluation of fixed tissue samples collected following the culture period identified insulin and glucagon-secreting cells in the SIS and FCS treated groups, however a higher frequency of insulin positive cells were detected consistently in the SIS treated group. A proliferation marker (PCNA) identified positive cells within both groups as well. This study suggests that co-culture of freshly isolated canine islets in medium supplemented with solubilized SIS can improve the post-culture recovery and in vitro islet function. Future investigations will focus on the cellular interactions of SIS, both in vitro and in vivo.

Dedifferentiated acinic cell carcinoma of the parotid gland: a distinct rarely described entity

A case of dedifferentiated acinic cell carcinoma of the parotid gland is presented. A 46-year-old man presented with a parotid gland mass. At surgery the tumor was found adherent to the temporal bone and cervical adenopathy was present. Treatment included radical parotidectomy and intraoperative radiotherapy. Histologically, the tumor was a composite of a usual low-grade acinic cell carcinoma and high-grade, poorly differentiated carcinoma. Cervical lymph node metastases were composed entirely of high-grade carcinoma. Immunohistochemically, both low- and high-grade malignant components were negative for p53 oncoprotein expression. Moreover, polymerase chain reaction and nonisotopic single-stranded conformational polymorphism analyses were consistent with a germ line configuration of the p53 gene, exons five through eight, in both low- and high-grade elements of the tumor. The literature on this unusual variant of acinic cell carcinoma is reviewed.

Quantitative criteria for clonality in the diagnosis of B-cell non-Hodgkin's lymphoma by flow cytometry

Fifty-three cases of B-cell non-Hodgkin's lymphoma (BNHL) and 41 cases of non-BNHL lesions were retrospectively evaluated for the quantitative features of restricted surface light chain expression, pan B-cell antigens, pan T-cell antigens, and T-helper and T-suppressor phenotype using flow cytometry. Decision limit analyses were applied to multiple quantitative indices of immunophenotype to establish criteria for the detection of clonal proliferation associated with BNHL or non-BNHL conditions. Two data expressions (percent population and relative ratios) were simultaneously analyzed. The percent population measures were amenable to parametric analyses; the ratio data were amenable to nonparametric analyses only. Acceptable diagnostic specificity and sensitivity were obtained using decision limits of 75% kappa light chain and 65% lambda light chain for the detection of clonal proliferations associated with BNHL. Comparable diagnostic criteria for light chain ratios of 3:1 and 2:1 were similarly confirmed for cases of kappa clonal and lambda clonal proliferations, respectively. Neither the percent of B-cells present nor the ratio of T-helper cells to T-suppressor cells were of utility in the diagnosis of BNHL. These data confirm the numerical criteria for clonality previously obtained by cell counting studies of immunocytochemical preparations and characterize quantitative criteria for aid in the diagnosis of BNHL based on restricted surface light chain expression as measured by flow cytometry.

Proliferating cell nuclear antigen (PCNA) in common epidermal lesions.. An immunohistochemical study of proliferating cell populations

A commercially available antibody to proliferating cell nuclear antigen was used to characterize and compare proliferating cell populations in paraffin sections of benign, premalignant, and malignant lesions of human epidermis using routine immunohistochemical techniques. Three patterns emerged. An ordered pattern was found in prurigo nodularis and keratoacanthoma, wherein moderately and strongly positive nuclei were distributed in a continuous, basal-suprabasal layer of relatively uniform thickness. There was graded loss and ultimate extinction of PCNA staining in progressively more superficial epidermal cells. A basal dysplastic pattern was found in actinic keratosis and squamous cell carcinoma. Nuclei of essentially all dysplastic cells of both categories expressed PCNA, with a preponderance of strongly positive nuclei. These were localized to basal-suprabasal zones that were often expanded. Loss of PCNA reactivity toward the surface was often abrupt. Bowen's disease exhibited a diffuse dysplastic pattern, wherein large numbers of moderately and strongly positive nuclei, in random array, were present in essentially full thickness distribution. In many fields, however, a layer of cytologically bland basal cells, with faint or no nuclear staining, was interposed between dysplastic epithelium and dermis. This study has demonstrated that proliferating cell populations in epidermal lesions can be assessed with simple, inexpensive methods. There were consistent differences between the proliferating cell populations of the various entities studied, differences that can be reasonably correlated with other known clinical, microscopic, and biologic features of the lesions. This technique should provide an interesting new avenue for study of diverse cutaneous diseases.

Malignant peritoneal mesothelioma in childhood with long-term survival

A diffuse, well-differentiated, malignant peritoneal mesothelioma (MPM) developed in a nine-year-old girl. She received limited chemotherapy and radiation therapy and is alive and well without clinical evidence of disease 109 months after diagnosis. The neoplastic cells stained immunohistochemically for cytokeratin and epithelial membrane antigen but were unreactive with B72.3, anti-carcinoembryonic antigen, and anti-Leu-M1. Ultrastructurally, the tumor cells had abundant desmosomes, numerous tonofilament bundles, and variable-length microvilli. These findings confirm the mesothelial nature of the cells. Features consistent with malignancy included DNA aneuploidy by flow cytometric analysis and diffuse peritoneal involvement. The three previously described survivors with MPM were also premenarchal girls. Some MPMs in premenarchal girls have an indolent biologic behavior similar to that of low-grade peritoneal serous neoplasia or well-differentiated papillary mesothelioma in adult women.

Plasminogen binding to rat hepatocytes in primary culture and to thin slices of rat liver

Human 125I-plasminogen bound readily to rat hepatocytes in primary culture at 4 degrees C and at 37 degrees C. Binding was inhibited by lysine and reversed by lysine, epsilon-aminocaproic acid, or nonradiolabeled plasminogen. The Kd for binding of 125I-plasminogen to hepatocytes was 0.59 +/- 0.16 mumol/L, as determined from the saturation isotherm by nonlinear regression (r2 = 0.99) and the Scatchard transformation by linear regression (r2 = 0.93). The number of sites per cell was 14.1 +/- 1.1 x 10(6). Fibrinogen synthesis and secretion by hepatocytes was insufficient to account for the major fraction of plasminogen binding, as determined by enzyme-linked immunosorbent assay (ELISA). Polyacrylamide gel electrophoresis and trichloroacetic acid precipitation studies demonstrated that plasminogen is neither activated nor degraded when bound to hepatocytes at 37 degrees C. Thin slices of whole rat liver (500 microns), isolated and prepared totally at 4 degrees C, bound 125I-plasminogen. Binding was inhibited by lysine. 125I-albumin binding to liver slices was minimal and not inhibited by lysine. Activation of plasminogen by tissue plasminogen activator (t-PA) was enhanced by hepatocytes in primary culture. When lysine was included in the media, the enhanced rate of activation was no longer observed. After activation with t-PA, much of the plasmin remained associated with hepatocyte surfaces and was partially protected from inhibition by alpha 2-antiplasmin. These studies suggest that hepatocyte plasminogen binding sites may provide important surface anticoagulant activity.

Inactivation of alpha 2-antiplasmin by limited reaction with cis-dichlorodiammineplatinum (II)

alpha 2-Antiplasmin (alpha 2AP), a serpin proteinase inhibitor with two methionine residues in its reactive center, was treated with cis-dichlorodiammineplatinum (II) (cis-DDP). This compound has been utilized previously to specifically modify methionine residues. After reaction, the alpha 2AP demonstrated decreased inhibitory activity against plasmin, miniplasmin, trypsin and chymotrypsin. The reduction in activity depended on the concentration of cis-DDP; however, the amount of activity retained by the treated alpha 2AP was equivalent with each of the four proteinases. alpha 2AP that was incubated with 1.0 mM cis-DDP for 3 h at 37 degrees C was 90% inactivated. These same conditions resulted in the binding of only 1.0-1.5 mol of platinum per mol of inhibitor. In experiments with lower concentrations of cis-DDP, the amount of incorporated platinum directly correlated with the amount of inactivated alpha 2AP (1:1 stoichiometry). Reactions and functions of alpha 2AP that do not result in proteinase inhibition were not affected by cis-DDP. Cleavage of alpha 2AP by elastase, which occurs near the proteinase inhibition site, was unaffected. In addition, the affinity of alpha 2AP for the K1-3 region of plasminogen remained unchanged after treatment. These data strongly suggest that the reaction of alpha 2AP with cis-DDP involves principally a single site on the inhibitor and that this site is critical for proteinase inhibitory activity. The most likely candidate is the P'1 methionine which is adjacent to the peptide bonds cleaved in the proteinase inhibitory reactions but not in the elastase reaction.

Quantitative distribution of the glycine receptor in the auditory brain stem of the gerbil

The concentration and relative distribution of glycine receptors were determined for gerbil brain stem auditory nuclei using 3H-strychnine and quantitative autoradiographic techniques. Significant binding was observed in the anteroventral cochlear nucleus, the dorsal cochlear nucleus, the lateral superior olivary nucleus, and the inferior colliculus. A non-uniform distribution of binding was seen in 3 of these nuclei, such that the greatest concentration of glycine receptors was located in the high-frequency regions. An analysis of neuron soma density suggested that the amount of post-synaptic membrane could partially explain the distribution of receptor.

In vivo tracer studies of glucose metabolism, cerebral blood flow, and protein synthesis in naloxone precipitated morphine withdrawal

Quantitative autoradiography of [14C]deoxyglucose, [14C]iodoantipyrine, and [14C]leucine was used to estimate regional cerebral glucose metabolism, cerebral blood flow, and cerebral protein synthesis, respectively, in rats during morphine dependence and withdrawal. Glucose metabolism was elevated in 19 of 26 selected brain regions; the elevations in glucose metabolism were similar when data were expressed as either optical density ratios or as calculated rate values of mumol/100 gm/min. Restraining the rats produced heterogeneous effects on glucose metabolism during morphine withdrawal (MW). Neither estimated cerebral blood flow nor cerebral protein synthesis were affected by morphine and/or naloxone treatments in either naive or morphine-dependent rats. The data demonstrate that changes in regional cerebral glucose utilization occur independently of blood flow changes and exclude the possibility that regional changes in glucose utilization occur as a consequence of large regional changes in protein synthesis rates in brain. These data confirm the utility of 2-deoxyglucose measures of MW as objective biochemical indices of opiate agonist and antagonist effects in vivo.

Somatostatin augments the spread of limbic seizures from the hippocampus

The role of the neuropeptide somatostatin in limbic seizures was studied using electrical stimulation of the hippocampus in kindled rats. Cysteamine, an agent which selectively and reversibly depletes brain somatostatin stores, had a biphasic action. An early proconvulsant effect was seen within a few hours, consisting of prolonged electrographic seizures in the hippocampus and more severe behavioral convulsions. A later anticonvulsant effect, maximal at 1 to 2 days and dissipating within a week, was manifested by less intense behavioral convulsions without change in the duration of electrical seizure activity. Both effects were dose-dependent. No change in afterdischarge thresholds was detected at any time after the administration of cysteamine. Intraventricular administration of somatostatin to animals with behavioral seizures attenuated by cysteamine treatment restored the responses to precysteamine levels. We conclude that somatostatin facilitates the spread of seizures over limbic circuits from a region of focal seizure initiation.

In vitro and in vivo distribution and binding of phenytoin to rat brain

The distribution and binding of phenytoin (PHT) were studied in rat brain using anatomically intact tissue. The pattern and kinetics of PHT distribution in vivo were examined with quantitative carbon-14 autoradiography. Initially gray matter levels were greater than white matter levels, but after 30 min the opposite condition was found. At a given time point, the levels of PHT among various gray matter structures as a group or among white matter structures as a group were uniform. The ratio of radioactivity in white matter to that in gray matter was 3:1 120 min after injection of radiolabeled PHT. Thin-layer chromatography showed only PHT in the brain 15 min after injection of PHT and both PHT and its hydroxylated metabolite [5-(p-hydroxyphenyl)-5-phenylhydantoin] 120 min after injection. The proportions of PHT and 5-(p-hydroxyphenyl)-5-phenylhydantoin were the same in white as in gray matter. Direct chemical measurements of brain samples obtained after coinjections of tracer amounts of radiolabeled PHT with increasing doses of unlabeled PHT corroborated the autoradiographic findings and revealed no displacement of the tracer by pharmacologic doses of the unlabeled drug. In vitro binding of PHT was investigated with sections obtained from frozen brains and with physiologically intact brain slices. Both high (4-10 nM) and low (1 microM) affinity conditions were examined. In no case was specific binding detected. Binding was greater in gray matter than in white matter in sections, whereas binding was greater in white matter than in gray matter in slices. We conclude that PHT distribution and binding reflect physico-chemical factors, such as lipid content, and physiological factors, such as blood flow and selective partitioning into white matter in living tissue, rather than specific receptors.

Time action profiles of regional cerebral glucose utilization during naloxone-precipitated morphine withdrawal

Time-dependent profiles of regional cerebral glucose utilization (RCGU) during morphine withdrawal (MW) were studied by varying the time of 2-deoxy-[14C]glucose (2-DG) administration after a maximal withdrawal-precipitating dose of naloxone was given to morphine-dependent rats. Heterogeneous and multiphasic time-action patterns of RCGU responses were found among 21 brain regions known to exhibit specific elevations in 2-DG labeling during MW. All MW-associated RCGU responses decreased when the interval between naloxone and 2-DG injection approximated the half-life of naloxone in the brain. Of the regions studied, time courses for metabolic responses in the lateral septum and lateral habenula most closely approximated the time course of naloxone availability in the brain. These results suggest that the earliest direct effects of naloxone on central nervous system metabolism in morphine-dependent rats occur in the lateral septum and lateral habenula.

Localization of D-2 dopamine receptors to intrinsic striatal neurones by quantitative autoradiography

Recent work with positron emission and single photon emission computed tomography has demonstrated the feasibility of studying striatal dopamine receptors in the living human brain. For the proper interpretation of these studies in normal and diseased states, the cellular localization of these receptors must be definitively established. It has been claimed, on the basis of receptor binding studies with tissue homogenates in rats, that 30-50% of striatal D-2 dopamine receptors are located on axons or terminals of the corticostriatal pathway. This finding has been incorporated into major reviews and classifications of dopamine receptors. The recent development of quantitative autoradiographic methods for diffusible ligands has facilitated the study of neurotransmitter receptors in cytoarchitechtonically intact tissue. Because this technique provides the necessary anatomic resolution that is lacking in homogenate binding studies, we have used it to re-examine the localization of striatal dopamine receptors. Here we present evidence that D-2 receptors are located exclusively on kainic acid-sensitive intrinsic neuronal elements in the striatum. We report that discrete cortical ablation does not alter 3H-spiperone binding to rat striatum and thus our results do not support the existence of D-2 dopamine receptors on the terminals of the corticostriatal pathway.

Regional saturation studies of [3H]naloxone binding in the naive, dependent and withdrawal states

We have examined the saturation features (Kd and Bmax) of [3H]naloxone binding in rat brain regions in cytoarchitectonically intact tissues of naive, morphine dependent and precipitated withdrawal states using quantitative film autoradiography. Sixty-one saturation experiments in 13 regions of naive rat brains yielded monophasic Eadie-Hofstee plots with a mean (+/- S.D.) Kd of 1.87 +/- 0.87 nM and a mean Bmax (+/- S.D.) of 101 +/- 66 fmol/mg. The 61 Kd values in naive rats described a normal distribution of regional binding affinities that may reflect the biological variation of a single high affinity binding site. Similar studies in the morphine dependent and precipitated withdrawal states showed no apparent changes in either the Kd or Bmax of regional [3H]naloxone binding. The possibility that in vitro preincubation of tissue sections masked potential alterations in [3H]naloxone binding was examined in competition studies of both morphine and naloxone for 2.0 nM [3H]naloxone binding to striatal sections. Preincubation had no effect on the ability of either opiate agonist or antagonist to compete for [3H]naloxone binding in the naive, morphine dependent or precipitated withdrawal states. The regional data comparing Kd and Bmax for [3H]naloxone binding in naive, morphine dependent and precipitated withdrawal states eliminated the possibility that previous efforts to demonstrate alterations in opiate binding were confounded by homogenization and/or limitations of gross dissection. Our data suggest that either potential changes in antagonist binding in dependent and withdrawal states can only be demonstrated under strict in vivo conditions or that post-binding transduction mechanisms are the sites of adaptive changes in naloxone sensitivity in the states of opiate dependence and withdrawal.

Quantitative film autoradiography for tritium: methodological considerations

The details of quantitative film autoradiography for tritium using tritium plastic standards were examined with respect to 3 issues: tritium tissue equivalent (TE) calibration; correction of autoabsorption differences for gray and white matter; and the use of carbon-14 standard sources as a method for quantifying tritium tissue images. Both 3H-tissue and 3H-plastic sources produced linear log-log relationships of 3H-concentration (nCi/mg source weight) vs source optical density (OD) over a reproducible OD range (0.080-0.800). The curves for both 3H-tissue and 3H-plastic were parallel; uncalibrated 3H-plastic standards exhibited a 4-fold higher autoabsorption over 3H-tissue sources for OD values in the linear range. Using chloroform extraction of brains from rats treated with either [14C]deoxyglucose ([14C]DG) or [3H]deoxyglucose ([3H]DG), we found neither isotope loss nor redistribution after defatting (30% reduction of tissue dry weight). After chloroform extraction, the OD values from both gray and white matter structures containing carbon-14 were unaltered. Gray matter OD values increased by 28.7 +/- 5.6% (mean +/- S.D.) in structures containing tritium; white matter structures containing tritium exhibited a 115.9 +/- 29.3% increase in OD after chloroform extraction. The increase in OD after chloroform extraction was a fixed percent for any given tritium OD value from unextracted tissue when the value was within the linear range of 0.080-0.800 OD units. The magnitude of the higher white matter autoabsorption for tritium was confirmed using tritium impregnated cow brain pastes of variable gray/white mixtures. Chloroform extraction of tissue from [3H]DG treated rats was therefore a suitable procedure for direct correction of regionally heterogeneous autoabsorption of tritium. Finally, the rates of image generation for tritium and carbon-14 sources were compared. The rate of increase of OD with increasing exposure time was found to be equal for 3H-tissue and 3H-plastic images; sources of carbon-14 in plastic, however, exhibited more accelerated rates of image generation when compared to tritium sources (i.e. 3H- and 14C-images did not covary with exposure time). The effect of non-covariance on tritium TE calibrated standards was the overestimation of OD values for 14C-plastic standards with increasing times of exposure (comparison of 4 week images to 1 week images showed errors of 35-40%). Use of carbon-14 sources to quantify tritium-generated images therefore required recalibration of 14C-plastic for all exposure times of interest.

Regional tritium quenching in quantitative autoradiography of the central nervous system

Direct corrections of regional differential tritium autoabsorption in quantitative autoradiography of the central nervous system are made using chloroform extraction of brain sections from rats receiving tritiated 2-deoxyglucose in vivo. Fifty-two regional quenching coefficients varied from 30% in gray structures to 100% in white structures. These data may be used to correct for regional quenching of tritium emissions in autoradiographic studies of rat brain.

Similar functional anatomy of spontaneous and precipitated morphine withdrawal

The distribution and magnitude of changes in regional cerebral glucose utilization were similar whether opiate withdrawal was spontaneous or naloxone induced.

Dose effects of naloxone on fixed morphine dependence: simultaneous behavioral and 2-deoxyglucose study in the rat

We have simultaneously studied regional cerebral glucose utilization (RCGU) and behavior during naloxone precipitated morphine withdrawal. For RCGU studies, 25 brain regions were analyzed that previously had been shown to participate in morphine withdrawal. Four established behavioral signs of morphine withdrawal were recorded: wet shakes, jumping, weight loss, and autonomic signs. Using a 10(4) range of naloxone dose (0.0005-5.0 mg/kg), dose dependent effects were found for 3 behaviors: jumping, weight loss and autonomic signs. The incidence of wet shakes did not correlate with naloxone dose. Increases in RCGU in several specific brain sites were also naloxone dose dependent. Naloxone dose dependent increases in RCGU during precipitated morphine withdrawal may be divided into 3 classes of responses: Class I structures (paraventricular, ventromedial, and lateral hypothalamus) exhibited their largest RCGU increases between 0.005 and 0.05 mg/kg of naloxone; Class II structures (preoptic areas, basal ganglia, anterior and intralaminar thalamic nuclei, mammillary nuclei, and certain midbrain regions) showed gradual RCGU increases across the 10(4) range of naloxone dose; and, Class III structures (diagonal band, medial and lateral septum, and the central amygdaloid nucleus) displayed large RCGU increases across 0.5-5.0 mg/kg of naloxone. Regression analysis of RCGU vs behavior showed correlations between Class I responses and autonomic signs (P less than 0.010); weight loss was correlated with all 3 classes of naloxone dose dependent RCGU responses during withdrawal (P less than 0.05). The strong positive correlation among these RCGU increases and certain morphine withdrawal behaviors supported the use of RCGU measurements in specific brain sites as a sensitive and objective biochemical indicator of the presence and severity of morphine dependence. In addition, this study demonstrates that changes in RCGU in different brain regions are heterogeneous with respect to naloxone dose and appear reproducibly along a continuum from mild to severe withdrawal.

Quantitative film autoradiography of opiate agonist and antagonist binding in rat brain

The binding of a radiolabeled opiate agonist ([3H]etorphine) and antagonist ([3H]naloxone) was studied using quantitative film autoradiography of rat-brain sections labeled by in vitro dipping methods. The binding activities of both [3H]naloxone and [3H] etorphine were saturable in three brain regions: noncluster striatum, nucleus accumbens and cingulate cortex. Eadie-Hofstee analysis of these regions yielded the following binding affinities and capacities: noncluster striatum binding affinity (KD) +/- S.E. = 1.59 +/- 0.23 nM, maximal binding capacity (Bmax) +/- S.E. = 28.3 +/- 1.9 fmol/mg, S.D. error of the raw data (Erad) = 6.4%; nucleus accumbens, KD +/- S.E. = 1.74 +/- 0.28 nM, Bmax +/- S.E. = 73.3 +/- 5.2 fmol/mg, S.D. (Erad) = 6.2%; cingulate cortex, KD +/- S.E. = 1.44 +/- 0.15 nM, Bmax +/- S.E. = 37.6 +/- 1.4 fmol/mg, S.D. (Erad) = 2.5%. A KD +/- S.E. = 1.72 +/- 0.29 nM, Bmax +/- S.E. = 74.1 +/- 5.3 fmol/mg, S.D. (Erad) = 5.0% was found for [3H]etorphine binding in the noncluster striatum. Hill plots of both [3H]naloxone and [3H]etorphine binding in noncluster striatum demonstrated an absence of cooperativity with slopes of 1.01 and 1.07, respectively. Stereospecificity of binding was confirmed by competition for 2.0 nM [3H]naloxone in the noncluster striatum with a levorphanol IC50 = 5.5 nM and a dextrorphan IC50 greater than 1000 nM. Rank order potency for competition for 2.0 nM [3H]naloxone binding in noncluster striatum was etorphine greater than naloxone greater than levorphanol greater than morphine greater than dextrorphan. The regional order of binding activities (femtomoles per milligram +/- S.D.) for 2.0 nM [3H]naloxone was as follows: striatal clusters (111.1 +/- 24.5) greater than interpeduncular nucleus (77.8 +/- 10.1) greater than central nucleus of amygdala (64.5 +/- 9.7) greater than nucleus accumbens (34.4 +/- 6.9) greater than median raphe (24.4 +/- 6.1) greater than striatal noncluster (23.3 +/- 3.5) greater than superior colliculus striatum grieseum (22.2 +/- 4.0). Thus, quantitative film autoradiography of brain sections labeled in vitro may be used to characterize the pharmacological binding properties of ligands in many small brain regions not amendable to study in membrane preparations.