Reinke's edema: investigations on the role of MIB-1 and hepatocyte growth factor.

Reinke's edema is a benign disease of the human vocal fold, which mainly affects the sub-epithelial layer of the vocal fold. Microscopic observations show a strongly oedematous epithelium with loosened intercellular junctions, a disruption of the extracellular connections between mucosal epithelium and connective tissue, closely adherent to the thyroarytenoid muscle. Thickening of the basal layer of epithelium, known as Reinke's space, high deposition of fibronectin and chronic inflammatory infiltration it is also visible. We analyzed, together with the hepatocyte growth factor (HGF), the expression level of MIB-1 in samples harvested from patients affected by Reinke's edema, in order to define its biological role and consider it as a possible prognostic factor in the follow-up after surgical treatment. We observed a moderate expression of HGF in the lamina propria of the human vocal fold and in the basal membrane of the mucosal epithelium. Our finding suggests that this growth factor acts as an antifibrotic agent in Reinke's space and affects the fibronectin deposition in the lamina propria. MIB-1, on the contrary, showed a weak expression in the basement membrane of the mucosal epithelium and a total absence in the lamina propria deep layer, thus suggesting that only the superficial layer is actively involved in the reparatory process with a high regenerative capacity, together with a high deposition of fibronectin. The latter is necessary for the cellular connections reconstruction, after the inflammatory infiltration.

Human gallbladder carcinoma: Role of neurotrophins, MIB-1, CD34 and CA15-3.

Gallbladder carcinoma is the most common biliary tract tumor and the fifth most common gastrointestinal tract cancer .The prognosis of gallbladder carcinoma is poor and less than 5% of the patients are still alive five years postoperatively. Gallbladder specimens were obtained during surgical operations performed in eleven patients for resection of a gallbladder carcinoma, and during five autopsies (control cases selected among patients who died from for other causes, excluding those suffering from biliary or hepatic diseases). Immunohistochemical characterization and distribution of neurotrophins, with their respective receptors, were analyzed. The actual role played by these neurotrophic factors in the general regulation, vascular permeability, algic responsiveness, release of locally active substances and potential tumorigenesis in the gallbladder and biliary ducts compartment remains controversial. Our study revealed an increased immunohistochemical expression of NGF and TrKA in the epithelium and in the epithelial glands of the gallbladder carcinoma together with an evident immunoreactivity for BDNF in the same neoplastic areas. An evident immunoreactivity for NGF, TrKA and BDNF was observed in control specimens of gallbladder obtained during autopsies, whereas a weak or quite absent immunoreactivity was observed in the same specimens for NT4, TrKC and p75. On the contrary an appreciable immunoreactivity for p75 was observed in the specimens harvested from patients with gallbladder carcinoma. We also investigated the expression of some known tumor markers such as MIB-1 (anti Ki-67), CD34 and CA15-3, to identify a possible correlation between the expression of these molecular factors and the prognosis of gallbladder carcinoma. They resulted highly expressed in the stroma (CD34 and CA 15-3) and in the epithelium/epithelial glands (MIB-1) of the neoplastic areas and appeared to be almost absent in the control cases, suggesting that these markers, taken together, could be adopted as a panel of prognostic factors in the evaluation of the gallbladder carcinoma.

Serum CA 15-3 is increased in pulmonary fibrosis.

BACKGROUND AND AIM OF THE WORK: Carbohydrate antigen CA 15-3 is a glycoprotein whose expression, aberrant intracellular localization and changes in glycosylation have been associated with a wide range of cancers. Pulmonary fibrosis represents the final evolution of a chronic inflammation and is defined by the overgrowth of fibroblasts and exaggerated extracellular matrix deposition. The aim of the present study was to evaluate the possible diagnostic role of CA 15-3 in fibrosis in different idiopathic interstitial pneumonias. METHODS: CA 15-3 was measured in serum samples from healthy subjects (n=25) and patients affected with idiopathic pulmonary fibrosis (IPF/UIP) (n=20), sarcoidosis (n=22) at different stages (I, II, and III) and systemic sclerosis (n=25). CA 15-3 protein expression was also evaluated by immunohistochemistry in 21 lung biopsies and in 6 primary lung fibroblasts cell lines. RESULTS: The CA 15-3 serum levels were significantly higher in patients with IPF/UIP and with clinically advanced sarcoidosis (stage III). Serum CA 15-3 levels were slightly increased in patients with systemic sclerosis. No difference was observed between serum CA 15-3 levels in patients with sarcoidosis at stages I and II compared with control subjects. In IPF/UIP and in sarcoidosis at stage III elevated CA 15-3 serum levels significantly correlated with decreased total lung capacity, decreased diffusing capacity of carbon monoxide and high resolution computed tomography findings. Immunohistochemical analysis showed an intense specific CA 15-3 staining in fibroblasts within fibroblastic foci, surrounding sarcoid granulomas and in all cell cultures of lung fibroblasts from IPF/UIP lungs. CONCLUSIONS: Our results indicate that increased CA 15-3 levels are associated with pulmonary interstitial damage, fibroblast activity and progression to fibrosis of the lung. Therefore, CA-15-3 may be considered a sensitive marker useful in the identification of patients with advanced fibrosis and more severe prognosis.

A possible role of BDNF in prostate cancer detection.

Many studies have demonstrated that both normal and malignant prostate cells respond to a variety of growth factors, while several significant differences were found between normal and tumoural cells. The aim of this study was to focus on the localization and distribution of the immuno-reactivity for neurotrophins (NTs) and neurotrophin receptors (NTRs) in normal, hyperplastic and prostate cancer cells, obtained from 40 subjects. We studied samples obtained from 16 prostate cancer (PC, retropubic radical prostatectomy), 20 benign prostatic hyperplasia (BPH, supra-pubic prostatectomy) and normal peripheral prostate tissue from four fresh male cadavers. Samples were examined via immunohistochemical techniques in order to detect the expression of nerve growth factor (NGF), brain derived neurotrophic factor (BDNF), neurotrophin 3 (NT3) and their own receptors TrkA, p75, TrkB and TrkC. We observed a high expression of BDNF and TrkB in PC and BPH, though no immuno-reactivity was found for p75. Low expression was reported by other NTs and NTRs in the normal peripheral prostate zone, BPH and PC. These data suggest a possible predictive role for NTs and NTRs, especially for BDNF and TrkB, in the diagnosis and/or management of prostate cancer. The absence of p75 expression confirms its supposed role in apoptotic phenomenon.

Immunohistochemical profile of some neurotransmitters and neurotrophins in the seminiferous tubules of rats treated by lonidamine.

Lonidamine (LND) or [1-(2,4-dichlorobenzyl)-1H-indazole-3-carboxylic acid] is an anticancer and antispermatogenic drug that exerts a large number of effects on tumor cells and germ cells. Sexually mature male Sprague-Dawley rats were housed at 22 degrees C on a 12-h light/12-h dark cycle 1 week before the experiments, with free access to food and water. LND was suspended in 0.5% methylcellulose at a concentration of 10 mg/mL and administered orally at the dose of 10 mL/kg (b.w.) as a single dose. Control rats received an equal amount of vehicle. Testes were removed, fixed for 24 h in 2% glutaraldehyde and 2% paraformaldehyde in 0.1 M sodium phosphate (pH 7.2 at 22 degrees C), rinsed with the same buffer, and stored at room temperature. From each sample, a block of tissue was removed by sectioning through the organ. After dehydration in ethanol at increasing concentrations (70-100%), each block was embedded in paraffin and serial 5 mm thick sections were cut using a rotatory microtome. The immunoreactivity for NTs has been observed in spermatogonia of untreated rats, while the rats treated with LND showed an immunohistochemical localization in all the stages of germinal cells. The generally well-expressed immunoreactivity for the neurotrophins receptors in treated rats observed in our study is presumably attributable to alterations of the receptors' structure and/or expression leading to changes of the activity, affinity, localization or protein interactions that may depend on sensitization of ion channels (induced by LND). Neurotrophins (NTs) appear to be interesting proteins for the modulation of sperm maturation and motility with a prominent role for the nerve growth factor (NGF), that may exert an autocrine or paracrine role. We therefore investigated the location and distribution of immunoreactivity for some neurotransmitters (SP, VIP, CGRP, nNOS, Chat), neurotrophins (NGF, BDNF, NT-3) and their own receptors (TrKA, TrKB, TrKC, p75) in the seminiferous tubules of male rats treated by LND in the light of the literature on this topic.

Conjoined lumbosacral nerve roots: observations on three cases and review of the literature.

Lumbosacral nerve root anomalies are a rare group of congenital anatomical anomalies. Various types of anomalies of the lumbosacral nerve roots have been documented in the available international literature. Generally speaking, these anomalies may consist of a bifid, conjoined structure, of a transverse course or of a characteristic anastomized appearance. Firstly described as an incidental finding during autopsies or surgical procedures performed for lumbar disk herniations and often asymptomatic, lumbosacral nerve root anomalies have been more frequently described in the last years due to the advances made in radiological diagnosis (metrizamide myelography and CT, MRI). Our study comprised three patients with conjoined lumbosacral nerve roots, representing 0.25% of a total of 1200 patients who underwent lumbosacral CT/MRI procedures in the Addolorata Hospital and in the Service of Neuroradiology of the University of Rome "La Sapienza" during the last three years (March 2001-March 2004). We report our experience with three cases of conjoined lumbosacral nerve roots and analyze the most important literature on this topic. MR imaging is a better diagnostic procedure (in comparison to CT) for the differentiation of nerve root anomalies and, in particular, coronal sections furnish a precise definition of the profile of the conjoined/enlarged rootlets. In fact, the accurate information derived from MRI of multiple planes may be priceless for the preoperative and diagnostic evaluation of lumbosacral nerve root anomalies.

Expression of neurotransmitters and neurotrophins in human adenoid tissue.

Mucosae-associated lymphoid tissues are richly innervated and the mucosae contain peptidergic nerve endings associated with different types of cells and macrophages. The lymphatic tissue is known to interact with the nervous system and several organs, implicated in the host response to a wide range of stressors, and is also richly innervated. We focussed our attention on the immune organs with particular regard to the human adenoid lymphatic tissues in order to investigate the neuroimmune links and the possible existence of relationships among different neurotransmitters and lymphocytes, macrophages, epithelial cells and nerve fibers by testing the expression of certain neurotransmitters and neurotrophins (NTs) with their own receptors.

Clinical implications of left ovarian vein incomplete duplicity with embryonic intersubcardinal anastomosis-derived branches.

During the dissection of a female human cadaver a case of a duplex ovarian vein was observed. It was unique in its upper course where it anastomosed with an inferior polar renal vein, which in turn was linked to an upper polar renal vein by means of a joining branch. It is hypothesised that this represent a persistent link between the left subcardinal vein and the left sacrocardinal vein, together with some branches of a venous net, which represent the embryological intersubcardinal anastomosis. The gonadal vein arises from the distal (or postrenal) left subcardinal vein portion; the left renal vein develops from the intersubcardinal anastomosis. The venous net derived from the intersubcardinal anastomosis may represent a bypass system in cases of left renal vein occlusion. Left gonadal vein duplicity may also play an important role in the anatomical basis of idiopathic left ovarian vein syndrome or left varicocele, and can lead to mistakes being made during venous sclerotherapy.

Neurotrophins and neurotrophin receptors in human lung cancer.

The expression of neurotrophins (NTs) and related high- and low-affinity receptors was studied in surgical samples of histologically diagnosed human tumors of the lower respiratory tract. The experiment was conducted with 30 non-small cell lung cancer specimens and in eight small cell lung cancer specimens by Western blot analysis and immunohistochemistry to assess expression and distribution of NT and NT receptor proteins in tissues examined. Immunoblots of homogenates from human tumors displayed binding of anti-nerve growth factor (NGF), brain-derived neurotrophic factor (BDNF), and NT-3 antibodies as well as of anti-tyrosine-specific protein kinase (Trk) A, TrkB, and TrkC receptor antibodies, with similar migration characteristics than those displayed by human beta-NGF and proteins from rat brain. A specific immunoreactivity for NTs and NT receptors was demonstrated in vessel walls, stromal fibroblasts, immune cells, and sometimes within neoplastic cell bodies. Approximately 33% of bronchioloalveolar carcinomas exhibited a strong membrane NGF and TrkA immunoreactivity, whereas 46% adenocarcinomas expressed an intense TrkA immunoreactivity but a weak immunostaining for NGF within tumor cells. Moreover, squamous cell carcinomas developed an intense TrkA immunoreactivity only within stroma surrounding neoplastic cells. A faint BDNF and TrkB immunoreactivity was documented in adenocarcinomas, squamous cell carcinomas, and small cell lung cancers. NT-3 and its corresponding TrkC receptor were found in a small number of squamous cell carcinomas within large-size tumor cells. No expression of low-affinity p75 receptor protein was found in tumor cells. The detection of NTs and NT receptor proteins in tumors of the lower respiratory tract suggests that NTs may be involved in controlling growth and differentiation of human lung cancer and/or influencing tumor behavior.

Alpha1-adrenergic receptor subtypes in peripheral blood lymphocytes of essential hypertensives.

OBJECTIVE: The expression of alpha1-adrenergic receptor subtypes in peripheral blood lymphocytes was investigated in 28 essential hypertensive patients as well as in the peripheral blood lymphocytes and aorta of spontaneously hypertensive rats (SHR) and normotensive Wistar-Kyoto (WKY) rats. METHODS: Alpha1-adrenergic receptors were quantified by radioligand binding assays, employing [3H]-prazosin as the radioligand in association with compounds displaying different degrees of selectivity for alpha1A-, alpha1B- and alpha1D-adrenergic receptor subtypes. RESULTS: The affinity of [3H]-prazosin binding was similar in peripheral blood lymphocytes of different stage essential hypertensive and normotensive subjects or of SHR and age-matched normotensive WKY rats as well as in the aortas of SHR and WKY rats. The radioligand binding assay revealed no change in the expression of alpha1-adrenergic receptors in peripheral blood lymphocytes of essential hypertensives compared with normotensive subjects; a moderate decrease of alpha1B-adrenergic receptors and an increase of alpha1D-adrenergic receptors. The relative densities of the alpha1-adrenergic receptor subtypes were similar in the three groups of essential hypertensives. In peripheral blood lymphocytes and in aorta of SHR, [3H]-prazosin binding was significantly reduced compared with normotensive WKY rats. The expression of alpha1-adrenergic receptor subtypes in peripheral blood lymphocytes of SHR was similar to that found in peripheral blood lymphocytes of essential hypertensives. CONCLUSIONS: Changes of lymphocyte alpha1-adrenergic receptor subtypes in essential hypertensives are similar to those observed in lymphocytes and vascular tissues of animal models of hypertension. This suggests that assays of lymphocyte alpha1-adrenergic receptors may represent an indirect marker of their involvement in essential hypertension.

[Inflammatory pseudotumor of the bladder: etiopathologic and clinical features]. / Pseudotumore infiammatorio vescicale: aspetti etiopatologici e clinici.

The Authors present a case of inflammatory pseudotumour (IPT) of the urinary bladder occurring in a 57-year-old female patient, who was referred to our department with haematuria, stranguria and hypogastric pain. Ultrasonographic, radiological and endoscopic examinations showed a sessile, ulcerated, easily bleeding bladder formation; urinary cytology revealed no atypical transitional cells. Abdomino-pelvic computed tomography analysis showed thickening of the bladder walls and infiltration of the perivesical fat. Histopathologically, the formation was indicated as an inflammatory pseudotumour (IPT) of the bladder. The patient underwent TURB (transurethral resection of the bladder) and was discharged clinically healed on postoperative day 4. A one-year follow up revealed no evidence of recurrence. On the basis of their experience and a thorough review of the literature review, the Authors discuss the clinico-pathological features of IPT of the bladder and the possible factors involved in the malignant transformation of IPT. In conclusion, the benign nature of the lesion is stressed.

Identification of dopamine plasma membrane and vesicular transporters in human peripheral blood lymphocytes.

Plasma membrane dopamine transporter (DAT), vesicular monoamine transporters (VMAT) type-1 and -2 and the expression of the dopaminergic markers dopamine and tyrosine hydroxylase were assessed in membranes and/or in cytospin centrifuged human peripheral blood lymphocytes. The radiolabeled DAT ligand [3H]GBR12935 was bound to peripheral lymphocytes in a manner consistent with the specific binding to a dopamine uptake system, with a dissociation constant similar to that found in striatum, but with a lower density of binding sites. On the other hand, no specific binding occurred in cerebellum used as a test tissue not expressing DAT. Western blot analysis using antibodies raised against amino or carboxy terminus of DAT or against VMAT-1 or VMAT-2 revealed labeling of single bands of approximately 76, 55 or 68 KDa, respectively, displaying similar migration characteristics in lymphocytes and test tissues used for comparison. Immunofluorescence revealed that anti-dopamine, anti-tyrosine hydroxylase, anti-DAT, anti-VMAT-1 and anti-VMAT-2 antibodies labeled the total population of cytospin-centrifuged lymphocytes mounted on microscope slides. Confocal laser microscopy demonstrated that dopamine and VMAT-2 immunoreactivity was developed mainly in cytoplasmic punctiform areas likely corresponding to vesicles and to a lower extent was associated to plasma membrane. Tyrosine hydroxylase immunoreactivity was diffused to cytoplasm and to plasma membrane of lymphocytes, whereas DAT and VMAT-1 immunoreactivity were located almost exclusively in lymphocyte plasma membrane and cytoplasm, respectively. Lymphocyte DAT characterized in this study has probably functional relevance as [3H]dopamine was taken up by intact lymphocytes and uptake was inhibited specifically by compounds known to affect dopamine transport. These findings indicate that human peripheral blood lymphocytes possess DAT plasma membrane and VMAT-1 and VMAT-2 transporters. Increasing evidence indicates that dopamine transporter changes may be related to neuronal injury. In view of this assessment of lymphocyte DAT and VMAT transporters can be considered for identifying pathologies characterized by impaired dopaminergic neurotransmission.

Dopamine receptors in human platelets.

The expression of dopamine receptors by human platelets was investigated by Western blot analysis and immunocytochemical techniques using antibodies raised against dopamine D1-D5 receptor protein. The influence of dopamine D1-like and D2-like receptor agonists on adrenaline-induced platelet aggregation was also investigated. Western blot analysis revealed that platelet membranes bind anti-dopamine D3 or D5 receptor protein antibodies, but not anti-D1, D2 or D4 receptor protein antibodies. Cytospin centrifuged human platelets exposed to anti-dopamine D3 or D5 receptor protein antibodies developed a specific immune staining, whereas no positive staining was noticeable in platelets exposed to other antibodies tested. Both the D1-like receptor agonist 1-phenyl2,3,4,5-tetrahydro-(1H)-3-benzazepine-7,8-diol hydrochloride (SKF 38393) and the D2-like receptor agonist 7-hydroxy-N,N-di-n-propyl-2-aminotetralin (7-OH-DPAT) dose-dependently inhibited adrenaline-induced platelet aggregation. These effects were decreased respectively by the D-like and D2-like receptor antagonists R(+)-2,3,4,5-tetrahydro-3-methyl-5-phenyl-1H-3-benzazepin-7-ol hydrochloride (SCH 23390) and (-)sulpiride. The above findings indicate that human platelets express dopamine D3 and D5 receptors probably involved in the regulation of platelet function.

Bahren types III and IVa testicular vein anomalies as a reason for failure in left idiopathic varicocele retrograde sclerotherapy. Ontogenic discussion and clinical implications.

Left testicular vein anatomy has received more attention due to the presence of competent or incompetent venous valves and bypassing anastomoses, which are involved in venographic diagnosis and embolisation of varicocele. The left gonadal vein develops, in both males and females, between the 5th and 7th intrauterine weeks, being derived from the distal or postrenal portion of the left subcardinal vein. The varicocele aetiologic hypothesis leads to ontogenetic disturbances in the development of the secondary venous system. Retrograde testicular venography shows the precise anatomy of the left pampiniform plexus, while anterograde testicular venography identifies the presence of the valve and possible continence. In the present case sclerotherapy could not be achieved due to testicular vein anomalies. Sclerotherapy versus surgical high ligature of the left testicular vein in cases of left idiopathic varicocele with testicular vein anomalies is discussed.

Influence of age on L-type Ca2+ channels in the pulmonary artery and vein of spontaneously hypertensive rats.

The influence of age on the density and localization of L-type Ca2+ channels was studied during development of hypertension in the pulmonary artery and vein of spontaneously hypertensive rats (SHR) and age-matched normotensive Wistar-Kyoto (WKY) rats by radioligand binding assay and light microscope autoradiography. SHR were examined at 6 weeks (juvenile, pre-hypertensive stage), 12 weeks (young, developing hypertension) and 24 weeks (mature, established hypertension). The dihydropyridine-type Ca2+ antagonist [3H]nicardipine was used as a radioligand. It was bound specifically to sections of rat pulmonary artery and vein. Dissociation constant (Kd) values were similar in WKY rats and SHR, whereas maximum density of binding sites (Bmax) values increased in SHR in comparison with WKY rats. This increase was noticeable from the pre-hypertensive phase. The pharmacological profile of [3H]nicardipine binding was similar in different age groups of either normotensive and hypertensive rats. Quantitative analysis of autoradiographs from SHR revealed a progressive increase of silver grains in smooth muscle of tunica media and to a lesser extent in the adventitia of pulmonary artery but not of pulmonary vein from pre-hypertensive stage to developing hypertension. No further changes were observed in established hypertension. The above data indicate that the density of L-type Ca2+ channels of pulmonary arteries is increased in SHR. This augmentation after the pre-hypertensive phase suggests the occurrence of dysregulation of Ca2+ handling in the pulmonary vasculature of developing SHR.

Reduced density of dopamine D2-like receptors on peripheral blood lymphocytes in Alzheimer's disease.

Clinical and pathological evidence points to an involvement of dopamine in Alzheimer's disease (AD). The present study was designed to assay dopamine D1-like and D2-like receptors on peripheral blood lymphocytes (PBL) in 20 patients with AD and in 25 healthy controls by radioligand binding assay techniques with [3H][R]-(+)-(-)chloro-2,3,4,5 tetrahydro-5-phenyl-1H-3-benzazepin-al-hemimaleate (SCH 23390) and [3H]7-hydroxy-N,N-di-n-propyl-2-aminotetraline (7OH-DPAT) as radioligands. The density of dopamine D1-like receptors and the affinity of [3H]SCH 23390 and [3H]7OH-DPAT binding to PBL were similar in both groups investigated. AD patients revealed a lower density of dopamine D2-like receptors on PBL than controls (P=0. 0016). The pharmacological profile of [3H]SCH 23390 and [3H]7OH-DPAT binding to PBL was consistent with the labeling of dopamine D5 and D3 receptor subtypes, respectively. The reduced density of dopamine D2-like receptors on PBL is consistent with the observation of changes in the expression of D2-like receptors in dopaminergic brain areas in AD. Our findings support the hypothesis of an involvement of dopamine in AD, even in those patients with no evidence of Parkinsonism, behavioral abnormalities or psychosis.

Neurotrophins and neurotrophin receptors in human pulmonary arteries.

The localization of neurotrophins (NTs) and NT receptors was analyzed in sections of human extra- and intrapulmonary arteries by Western blot analysis and immunohistochemistry. In extrapulmonary branches of human pulmonary artery, NT and NT receptor immunoreactivity was located in the tunica intima, within endothelium, in the tunica media, within smooth muscle and in the tunica adventitia. In different sized intrapulmonary arteries, NT and NT receptor immunoreactivity was observed primarily in the tunica adventitia. A faint NT and NT receptor immunoreactivity was observed in the tunica media of large-sized branches of intrapulmonary arteries, but not within medium- or small-sized intrapulmonary vessels or in tunica intima of different sized intrapulmonary arteries. These findings suggest that NTs may have a role in the control of vascular responses in the pulmonary system acting as local paracrine or autocrine mediators. The possible relevance of the NT system in human pulmonary vasculature identified in this study is discussed.

Localization of dopamine receptor subtypes in systemic arteries.

Dopamine D1-D5 receptor protein immunoreactivity was investigated in different sized pial, renal and mesenteric artery branches using immunohistochemical techniques and anti-dopamine D1-D5 receptor protein antibodies. Faint dopamine D1 receptor protein immunoreactivity was observed in smooth muscle of tunica media of pial, renal and mesenteric artery branches. Dopamine D2 receptor protein immunoreactivity was located in the adventitia and adventitia-media border of pial and renal artery branches and to a lesser extent of mesenteric artery branches. No dopamine D3 receptor protein immunoreactivity was observed in pial and mesenteric arteries. In renal arteries a moderate dopamine D3 receptor immunoreactivity was detectable in the adventitia and adventitia-media border. A strong dopamine D4 receptor protein immunoreactivity displaying the same localization of dopamine D2 receptor protein was observed in pial and mesenteric arteries, but not in renal artery branches. Moderate dopamine D5 receptor protein immunoreactivity was observed in smooth muscle of the tunica media of pial, renal and mesenteric artery branches. Bilateral removal of superior cervical ganglia, from which sympathetic supply to cerebral circulation originate abolished dopamine D2 and D4 receptor protein immunoreactivity in pial arteries but was without effect on dopamine D1 and D5 receptor protein immunoreactivity. These findings indicate that systemic arteries express dopamine D1-like (D1 and D5) and D2-like (D2, D3 and D4) receptor subtypes displaying respectively a muscular (postjunctional) and prejunctional localization. The specific distribution of dopamine D2-like receptor subtypes in systemic arteries suggests that they may have a different role in regulating blood flow through the vascular beds investigated.

Migraine patients show an increased density of dopamine D3 and D4 receptors on lymphocytes.

Recent studies have revealed peculiar functional and genetic features of dopamine receptors in migraine. As peripheral blood lymphocytes (PBL) may represent a tool for peripheral detection of neuroreceptors, we compared the expression of dopamine D3 (DRD3) and D4 (DRD4) receptors on PBL in migraine patients and in healthy controls using radioligand binding assay techniques in the presence of antidopamine D2-like receptor antibodies. The dopamine D2-like receptor agonist [3H]7-OH-DPAT was used as a radioligand. An increased density of both DRD3 (P=0.0006) and DRD4 (P=0.002) on PBL was observed in migraineurs compared with controls. This up-regulation might reflect central and/or peripheral dopamine receptor hypersensitivity due to hypofunction of the dopaminergic system. These findings support the view that dopamine D2-like receptors are involved in the determination of the so-called migraine trait, which may help to elucidate several clinical features of the disease.

Microanatomical localization of dopamine receptor protein immunoreactivity in the rat cerebellar cortex.

Dopamine (DA) receptor subtype localization was investigated in rat cerebellar cortex using immunohistochemical techniques with antibodies raised against D1-D5 receptor protein. A faint D1 receptor protein immunoreactivity was developed in molecular and Purkinje neurons layers. D2 receptor protein immunoreactivity was found primarily in cerebellar white matter followed by molecular and granular layers and Purkinje neurons. Antibodies against D2S receptor protein were localized in molecular layer and to a lesser extent, in granular layer. A few Purkinje neurons displayed a faint D2S receptor protein immunoreactivity. D3 receptor protein immunoreactivity was observed primarily in molecular and in Purkinje neurons layers of lobules 9 and 10. A faint D3 receptor protein immunoreactivity was also localized in Purkinje neurons and to a lesser extent, in molecular and granular layers of cerebellar lobules 1-8. D4 receptor protein immunoreactivity was found in cerebellar white matter. A pale immunostaining was also visualized in molecular layer. D5 receptor protein immunoreactivity was localized primarily in molecular and Purkinje neurons layers and to a lesser extent, in granular layer and in white matter. The above results indicate that rat cerebellar cortex expresses the DA receptor subtypes so far identified. Purkinje neurons, which are the only efferent neurons of cerebellum, are richest in DA receptor protein immunoreactivity. This suggests that dopaminergic neurotransmission may modulate efferent inputs from cerebellum. The localization of the majority of D2 and D4 and of a faint D5 protein receptor immunoreactivity in cerebellar white matter suggests that these receptors may be presynaptic and transported axonally.