Minilaparotomic incision for haemorrhagic corpus luteum: a case report

Corpus luteum cyst rupture with consequent hemoperitoneum is a common cause of admission to the emergency room. This condition is frequently misdiagnosed because of overlapping of clinical findings in acute gynecologic diseases. However, an incorrect identification may lead to delay in surgical treatment, which can Romabe a life-threatening condition. Ultrasound (US) is the first technique used for diagnosis that can confirm or dismiss the presence of intraperitoneal fluid. Secondly, the contrast-enhanced computed tomography (CT) is the quickest way to identify the site of active bleeding and to establish the correct management of the clinical condition. Herein, we report a case of a 19-years-old girl with acute abdominal pain correctly identified by diagnostic images and treated with mini-invasive surgery techniques in order to quickly act without clinic and aesthetic sequelae.

Intracesarean removal of two huge fibroids occupying the whole uterine fundus: a case report

Uterine fibroid is an estrogen-dependent mass growing during pregnancy. Caesarean myomectomy (CM) is a controversial procedure. A 35-year-old obese (106 Kg) patient gravida 2 para1 (caesarean section), undergoing caesarean section, had two myomas occupying the whole uterine fundus (104.2 mm and 50 mm respectively). Intracesarean myomectomy was carried out after extraction foetus (Apgar score: 9/10). Postoperative course was uneventful and patient was discharged after four days.

Neoplastic sigmoid-uterine fistula. An exceptional complication of large intestine cancer

Neoplastic sigmoid-uterine fistula is an extremely rare condition because the uterus is a thick and muscular organ. A 74-year-old woman was admitted to the First Aid Station suffering from abdominal pain and foul smelling vaginal discharge. Gynaecological examination showed fecal drainage from the cervical orifice, while the uterus was regular in size but very firm and painful. Ovaries and fallopian tubes were not palpable owing to abdominal tenderness. Ultrasounds reveled inhomogeneous thickening of uterine cavity, without detecting fistula. Contrast Medium CT (CMCT) showed Douglas' recto-uterine pouch occluded. The sigmoid wall was very thin exception a site where a fistula was suspected. At the surgery severe adhesions of the sigma-rectum with the posterior uterine wall were observed. After adhesiolysis, 18 cm colon-sigma-rectum was removed. Total hysterectomy with salpingooophorectomy was performed. Lymphadenectomy ended the procedure. Anatomical specimen confirmed sigmoid-uterine fistula. At histology a mildly differentiated adenocarcinoma of sigma-rectum was shown. Postoperative course was uneventful. Such a case of neoplastic sigmoiduterine fistula has not been reported so far.

Nuck canal cyst involving right femoral vein: management and therapy of a rare clinical case

We present a very rare case of a 49-year old woman suffering from Nuck canal cyst reaching and compressing femoral vein. Nuck canal cyst is very uncommon event because the pouch accompanying the gubernaculum during intrauterine descent of ovaries usually obliterates, whereas when it persists a cystic cavity containing citrine fluid develops. A gravid 0 para 0 49 old woman was admitted to Catania University Surgery Department owing to suspected lymphatic tumor compressing right femoral vein and causing groin pain with ipsilateral leg partial stasis. Patient believed right venous stasis was due to fibromatous uterus. Ultrasounds and computed tomography (CT) scan defined size (7.1 × 4.2 × 1.5 cm), structure (cystic) of mass and its relation with femoral vein, although they were not diriment for diagnosing its nature. Color Doppler detected circulatory function of compressed femoral vein. Surgery was challenging and Nuck cyst was removed after accurate separation from the right femoral venous walls. A case of Nuck cyst involving femoral vein has never been reported so far.

CT-guided drainage with percutaneous approach as treatment of E. Faecalis post caesarean section severe abscess: case report and literature review

We report a case of a 32-year old woman with severe pelvic abscess formation who was readmitted to the hospital after ten days of postoperative caesarean course. The patient had undergone emergency caesarean section (CS) for acute foetal sufferance during expulsive period and following three days had been discharged regularly. Enterococcus Faecalis was isolated from purulent material. A prompt antibiotic therapy was carried out, therefore clinic condition did not improve. A percutaneous Computed Tomography (CT)-guided drainage of the abscess was planned. Under local anesthesia abscess was drained. The hospitalization stay allowed monitoring the patient's clinical condition and laboratory blood panel until normalization of all parameters.

A rare case of trichilemmal ovarian carcinoma. Case report and review of the literature

Trichilemmal ovarian carcinoma is very rare. A 52-years-old woman was admitted to University Hospital Department suffering from pain in the left iliaca fossa lasting for three months. Uterus was normal in size, painless as well as right adnexum. On the left site ovary was increased in volume and slightly sore. Transvaginal ultrasounds showed a 97x65x86 mm mixed vascularized unilocular mass. CT scan detected a pelvic expansion with a heterogeneous density due to the presence of different structures varying from fat to bone tissue. A proper informed consent was obtained and a suprapubic transversal laparotomy according to Pfannenstiel was carried out. Ovarian mass and ipsilateral tube were removed with no rupture. The anatomical extemporaneous result was of benign dermoid cyst. The postoperative course was uneventful and after three days the patient was discharged in regular conditions and was recommended to come for final anatomical result. Following a month, the final histological answer was of 15 mm trichilemmal malignant tumor in a context of a large benign dermoid cyst. The neoplastic lesion appears to be entirely contained within the limits of the swollen mass. The outer surface was with no lesions. A case of trichilemmal malignant tumor involving ovary has not been published so far.

Colorectal cancer in aged patients. Toward the routine treatment through laparoscopic surgical approach

AIM

Colorectal cancer is one of the most common malignancies in general population. The incidence seems to be higher in older age. Surgery remains the treatment of choice and laparoscopic approach offers numerous benefits. We report our personal experience in elderly patients operated on for colorectal cancer with laparoscopic resection.

PATIENTS AND METHODS

From January 2003 to September 2013, out of 160 patients aged 65 years or older and operated with minimally invasive techniques, 30 cases affected by colorectal cancer and operated on with laparoscopic approach were analyzed in this study.

RESULTS

Male/female ratio was 1.35 and mean age 72 years. Constipation, weight loss, anemia and rectal bleeding were the most commonly reported symptoms. Lesions involved descending-sigmoid colon in 53% of cases, rectum in 37% and ascending colon in 10%. Among laparoscopic colo-rectal operations laparoscopic left colectomy was the most frequently performed, followed by right colectomy, abdominoperineal resection and Hartmann procedure. Operative times ranged from 3 to 5 hours depending on surgical procedure performed. Mean hospital stay was 6 days (range 4-9). Conversion to open approach occurred only in a case of laparoscopic right colectomy (3%) for uncontrolled bleeding. A single case of mortality was reported. In two cases (7%) anastomotic leakage was observed, conservatively treated in one patient and requiring reoperation in the other one.

CONCLUSIONS

Laparoscopic colorectal surgery is feasible and effective for malignancies in elderly population offering several advantages including immunologic and oncologic ones. However an experienced surgical team is essential in reducing risks and complications.

Hydronephrosis and utero-vaginal prolapse in postmenopausal women: management and treatment

INTRODUCTION

Pelvic organ prolapse is a multifactorial disease. Aim was to evaluate the effect of the whole surgical correction of pelvic floor on hydronephrosis due to severe prolapse.

PATIENTS AND METHODS

A retrospective case study on 250 patients presenting with severe uterovaginal prolapse was carried out.

RESULTS

Hydronephrosis was found in 32/234 (13.7 %). All patients underwent hysterectomy, vaginal apex axial suspension, posterior and anterior repair, vaginally. Prepubic TICT (Tension free Incontinence Cystocoele Treatment) was done in 38 cases (3 with hydronephrosis). Of the 32/234 (13.7 %) patients with hydronephrosis, 18/32 (56.25%) had complete resolution of hydronephrosis after treatment, 14/32 (43.75%) had a reduction of calico-pyelic dilatation, among them 8 patients had a second degree and 6 a first degree of hydronephrosis.

CONCLUSIONS

Vaginal-hysterectomy, axial apex suspension, anterior and posterior repair resulted in either complete resolution or improvement of hydronephrosis. Prepubic TICT did not interfere on mechanical obstruction and maintained postoperative continence in the event of occult Stress Urinary Incontinence (SUI).

Ovulation induction with clomiphene citrate and metformin in women with polycystic ovary syndrome

AIM

Polycystic ovary syndrome (PCOS) is one of the most common causes of ovulatory infertility. It is an endocrine disorders characterized by a high level of male hormones (androgens) and frequent anovulatory cycles associated with multiple ovarian microcysts. The aim of this paper was to evaluate effects of a Clomiphene citrate alone versus a combined treatment (Metformin and Clomiphene citrate).

METHODS

A total of 60 women with PCOS and infertility were evaluated. Inclusions criteria were: age 26-34 years, nulliparity, above 3 years of sterility, multiple ovarian microcysts, BMI>27.5, oligomenorrhea/amenorrhea, hyperandrogenism and normal male fertility. Four patients were excluded (renal damage 2, tubal occlusion 1 and Pelvic Inflammatory Disease 1). The remaining 56 were divided into 2 groups: group A were inducted with Clomiphene Citrate alone, while group B were inducted with Clomiphene citrate and Metformin.

RESULTS

In group A we obtained ovulation in 20 women (71.4%), 8 pregnancies (28.5%) and one (3.5%) spontaneous abortion. In group B we obtained ovulation in 24 women (85.7%), 15 pregnancies (53.5%) and no spontaneous abortions.

CONCLUSION

Combined treatment was found to be more effective (53.5) in improving pregnancy rate compared to monotherapy (28.5%).

Unexplained infertility and ovulatory induction with menopausal gonadotropins

AIM

Unexplained infertility affects 30% of infertile couples. Management depends on duration of infertility and age of female partner. Ovulation induction, together with intrauterine insemination, is commonly offered to couples with infertility of unknown origin. Intrauterine insemination gained its popularity because it is simple, non-invasive and cost-effective technique. The association with pharmacological stimulation is suitable to induce follicular maturation. The most used drugs to induce ovulation are clomiphene citrate and menopausal or recombinant gonodotropins. The aim of this paper was to evaluate the success rate after homologous intrauterine insemination (IUI) combined with menopausal gonadotropins stimulation.

METHODS

A total of 90 couples were evaluated. Twelve couples (13.3%) were excluded from the treatment (6 vaginal infections, 4 tubal occlusions and 2 male infertility). Informed consent was applied for every couple. The remaining 78 couples were divided in two groups: group A (39 couples) were inducted with menopausal gonadotropins, while group B (39 couples) underwent placebo (multivitamin).

RESULTS

In group A (gonadotropins) 25 (64.1%) pregnancies and 2 (5.1%) abortion were registered, while in group B (placebo) there were 7 (17.9%). pregnancies and 1 (2.5%) abortion.

CONCLUSION

Ovulation inductions with menopausal gonadotropins, together with intrauterine insemination, improves fecundity in patients with infertility of unknown origin without recur to more invasive techniques.

Ovulation induction with clomiphene citrate for infertile couple

AIM

Among couples unable to conceive without any identifiable cause, 30% are defined as having unexplained infertility. Management depends on duration of infertility and age of female partner. In order to increase pregnancy rate, couples with infertility of unknown origin can undergo ovulation induction and intrauterine insemination. These techniques are able to increase pregnancy rate in case of unexplained infertility. Clomiphene citrate and menopausal or recombinant gonodotropins are the most used drugs to induce ovulation. Aim of the present study was to evaluate the success rate after homologous intrauterine insemination (IUI) combined with clomiphene citrate (CC) stimulation.

METHODS

A total of 77 couples were evaluated. Nine couples (11.6%) were excluded from the treatment (vaginal infections 4, tubal occlusions 3 and male sterility 2). Informed consent was applied for every couple. The remaining 68 couples were divided in two groups: group A (34 couples) were inducted with CC, while group B (34 couples) underwent placebo (multivitamin).

RESULTS

In group A (CC) 15 (44.1%) pregnancies and 3 (8.8%) abortion were registered, while in group B (placebo) there were 4 (11.7%) pregnancies and 1 (2.9%) abortion.

CONCLUSION

Ovulation inductions with CC, together with intrauterine insemination, improves fecundity in patients with infertility of unknown origin with no need to recur to more invasive techniques.

A didactic protocol for labour and delivery: the partogram

AIM

The aim of this paper was to evaluate the didactic protocol on the management of both labour and birth.

METHODS

Selection criteria were carried out with randomized, quasi-randomized controlled trials and other relevant articles involving a comparison of partogram with no partogram, or comparison between different partogram designs. A printed alert and/or action lines are designed to prevent the deviation. Particularly partograms where divided in: 1) partogram versus no partogram in labour-delivery; 2) partogram with two-hour action line versus partogram with four-hour action line; 3) partogram with two-hour action line versus partogram with three-hour action line; 4) partogram with three-hour action line versus partogram with four-hour action line; 5) partogram with alert line versus partogram with alert and action line; 6) earlier versus later intervention.

RESULTS

We included twenty-eight studies in this review, involving 7 827 women; six studies assessed partogram versus no partogram and the remainder assessed different partogram designs. There was no evidence of significant difference between partogram and no partogram in caesarean section. When compared the use or less of partogram in vaginal deliveries, this tool with defined management protocols prevents obstructed labour (protracted phase or arrest of dilatation). Quality monitoring of the labour with the partogram will reduce the morbidity and mortality in both mother and newborn. Deviation of the curve from the standard partogram is an alert graphic expression of risk and moves forward an adequate management of treatment. Regarding the use of partogram as didactic protocol, it is considered useful in the comprehension of the various evolutions of labor and delivery.

CONCLUSION

On the basis of literature, the data regarding the use of partogram is controversial. Regarding elective caesarean section partogram doesn't give any advantages owing to the absence of labor. Relating the employ of partogram in labour, it is helpful for correcting the deviation from the normality, permitting the opportune use of both drugs (oxytocin) and procedures (amniotomy). Even if the literature does not recommend a routine use of the partogram as part of standard labour management, it always represents an instrument for a better determination of the parameters evaluated (dilatation, mechanical curve, contractions). Both physicians and midwives have to be trained to a correct use the partogram in order to have satisfactory results. A challenge to improve the graph and facilitate the compilation of the model should be addressed. Further trial evidence is required to establish the real and significant utility of partogram. Besides, the partogram is a practical graph for medico-legal evaluation in case of contentiousness.

Activation of endogenous neural stem cells in the adult human brain following subarachnoid hemorrhage

In the adult human brain, the presence of neural stem cells has been documented in the subgranular layer of the dentate gyrus of the hippocampus and in the subventricular zone of the lateral ventricles. Neurogenesis has also been reported in rodent models of ischemic stroke, traumatic brain injury, epileptic seizures, and intracerebral or subarachnoid hemorrhage. However, only sparse information is available about the occurrence of neurogenesis in the human brain under similar pathological conditions. In the present report, we describe neural progenitor cell proliferation in the brain of patients suffering from subarachnoid hemorrhage (SAH) resulting from ruptured aneurysm. Ten cerebral samples from both SAH and control patients obtained, respectively, during aneurysm clipping and deep brain tumor removal were analyzed by reverse transcription followed by polymerase chain reaction (RT-PCR) and/or immunohistochemistry (IHC). In tissue specimens from SAH patients, RT-PCR and IHC revealed the expression of a variety of markers consistent with CNS progenitor cells, including nestin, vimentin, SOX-2, and Musashi1 and -2. In the same specimens, double immunohistochemistry followed by confocal analysis revealed that Musashi2 consistently colocalized with the proliferation marker Ki67. By contrast, no such gene or protein expression profiles were detected in any of the control specimens. Thus, activation of neural progenitor cell proliferation may occur in adult human brain following subarachnoid hemorrhage, possibly contributing to the promotion of spontaneous recovery, in this pathological condition.

Extensive training in a maze task reduces neurogenesis in the adult rat dentate gyrus probably as a result of stress

It has recently been shown that hippocampal neurogenesis can be modulated either directly or indirectly by ascending cholinergic inputs from the basal forebrain. In the present work, we sought to address whether extended training in a spatial navigation task would affect hippocampal neurogenesis in the presence of a severe and selective cholinergic depletion. Young female rats received stereotaxic injections of the immunotoxin 192 IgG-saporin into the basal forebrain nuclei and/or the cerebellar cortex. Starting from 4 to 5 weeks post-lesion, and for the subsequent 2 weeks, the animals were trained on paradigms of reference and working memory in the water maze and received single daily i.p. injections of bromodeoxyuridine (BrdU) at the end of each testing session. In line with previous observations, a dramatic 80% decrease in neuron proliferation was seen in the dentate gyrus of lesioned animals, as compared to vehicle-injected or intact controls. Interestingly, however, rats subjected to maze training over 2 weeks, irrespective of their learning success, exhibited significantly fewer newborn neurons than matched controls with no maze exposure. Thus, at least for the type of task used here, which has previously been shown to impose a certain degree of stress, extended training and learning does not appear to affect proliferation in the dentate gyrus.

Maternal exposure to the antiepileptic drug vigabatrin affects postnatal development in the rat

The objective was to investigate, in the rat, the effects of maternal exposure to vigabatrin (VGB) on the postnatal motor-cognitive behaviour of the offspring. We used an experimental evaluator-blind, placebo-controlled study in the rat. Ten pregnant rats were divided into five groups and treated with different doses of VGB (250, 500, 750, 1000 mg/kg/day) or placebo from gestation day (GD) 6 to GD10. After delivery, 56 pups (40 pups prenatally exposed to VGB and 16 pups exposed to placebo) were evaluated for motor-cognitive behaviour throughout postpartum day 40. At the end of testing sessions the animals were sacrificed and brain tissues processed for biochemical analysis of GABA levels. Body weight of pups and young rats whose mothers were treated with a dose of 750 mg/kg/day were significantly lower both at birth and during the whole postnatal life with respect to the control groups. Young rats of this group exhibited impaired performance in both the open-field and water maze tasks. Brain GABA contents were dramatically increased in this group of rats. No other significant nutritional, biochemical or behavioural changes were observed after treatments with doses of VGB lower than 750 mg/kg/day. The exposure to a dose of 1000 mg/kg caused abortion. Maternal exposure to VGB at relatively high doses (750 mg/kg/day) is likely to cause some important changes of the nutritional status during the pre- and postnatal life. Thus, the biochemical and cognitive abnormalities observed in this study could be related to some disturbances of brain development induced by malnutrition and/or to a disturbance of neuronal programming of the gabaergic system.

Selective cholinergic immunolesioning affects synaptic plasticity in developing visual cortex

Cholinergic neurotransmission is known to affect activity-dependent plasticity in various areas, including the visual cortex. However, relatively little is known about the exact role of subcortical cholinergic inputs in the regulation of plastic events in this region during early postnatal development. In the present study, synaptic transmission and plasticity in the developing visual cortex were studied following selective immunotoxic removal of the basal forebrain cholinergic afferents in 4-day-old rat pups. The lesion produced dramatic cholinergic neuronal and terminal fibre loss associated with decreased mRNA levels for the M1 and M2 muscarinic receptors, as well as clear-cut impairments of long-term potentiation (LTP) in visual cortex slices. Indeed, after theta burst stimulation of layer IV a long-term depression (LTD) instead of an LTP was induced in immunolesioned slices. This functional change appears to be due to the lack of cholinergic input as exogenous application of acetylcholine prevented the shift from LTP to LTD. In addition, lesioned rats showed an increased sensitivity to acetylcholine (ACh). While application of 20 microm ACh produced a depression of the field potential in immunolesioned rat slices, in order to observe the same effect in control slices we had to increase ACh concentration to up to 200 microm. Taken together, our results indicate that deprivation of cholinergic input affects synaptic transmission and plasticity in developing visual cortex, suggesting that the cholinergic system could play an active role in the refinement of the cortical circuitry during maturation.

Septal cholinergic neurons suppress seizure development in hippocampal kindling in rats: comparison with noradrenergic neurons

Widespread lesions of forebrain cholinergic or noradrenergic projections by intraventricular administration of 192 IgG-saporin or 6-hydroxydopamine, respectively, accelerate kindling epileptogenesis. Here we demonstrate both quantitative and qualitative differences between the two lesions in their effects on hippocampal kindling in rats. Epileptogenesis was significantly faster after noradrenergic as compared to cholinergic denervation, and when both lesions were combined, kindling development resembled that in animals with 6-hydroxydopamine lesion alone. Furthermore, whereas the 192 IgG-saporin lesion promoted the development only of the early stages of kindling, administration of 6-hydroxydopamine or both neurotoxins accelerated the late stages also. To investigate the contribution of different subparts of the basal forebrain cholinergic system to its seizure-suppressant action in hippocampal kindling, 192 IgG-saporin was injected into medial septum/vertical limb of the diagonal band of Broca or nucleus basalis magnocellularis, leading to selective hippocampal or cortical cholinergic deafferentation, respectively. The denervation of the hippocampus facilitated kindling similar to the extensive lesion caused by intraventricular 192 IgG-saporin, whereas the cortical lesion had no effect. These results indicate that although both noradrenergic and cholinergic projections to the forebrain exert powerful inhibitory effects on hippocampal kindling epileptogenesis, the action of the cholinergic system is less pronounced and occurs specifically prior to seizure generalization. In contrast, noradrenergic neurons inhibit the development of both focal and generalized seizures. The septo-hippocampal neurons are responsible for the antiepileptogenic effect of the cholinergic system in hippocampal kindling, whereas the cortical projection is not significantly involved. Conversely, we have previously shown [Ferencz I. et al. (2000) Eur. J. Neurosci., 12, 2107-2116] that seizure-suppression in amygdala kindling is exerted through the cortical and not the hippocampal cholinergic projection. This shows that, depending on the location of the primary epileptic focus, i.e. the site of stimulation, basal forebrain cholinergic neurons operate through different subsystems to counteract seizure development in kindling.

Basal forebrain neurons suppress amygdala kindling via cortical but not hippocampal cholinergic projections in rats

Intraventricular administration of the immunotoxin 192 IgG-saporin in rats has been shown to cause a selective loss of cholinergic afferents to the hippocampus and cortical areas, and to facilitate seizure development in hippocampal kindling. Here we demonstrate that this lesion also accelerates seizure progression when kindling is induced by electrical stimulations in the amygdala. However, whereas intraventricular 192 IgG-saporin facilitated the development of the initial stages of hippocampal kindling, the same lesion promoted the late stages of amygdala kindling. To explore the role of various parts of the basal forebrain cholinergic system in amygdala kindling, selective lesions of the cholinergic projections to either hippocampus or cortex were produced by intraparenchymal injections of 192 IgG-saporin into medial septum/vertical limb of the diagonal band or nucleus basalis, respectively. Cholinergic denervation of the cortical regions caused acceleration of amygdala kindling closely resembling that observed after the more widespread lesion induced by intraventricular 192 IgG-saporin. In contrast, removal of the cholinergic input to the hippocampus had no effect on the development of amygdala kindling. These data indicate that basal forebrain cholinergic neurons suppress kindling elicited from amygdala, and that this dampening effect is mediated via cortical but not hippocampal projections.

Release properties and functional integration of noradrenergic-rich tissue grafted to the denervated spinal cord of the adult rat

Noradrenaline- (NA-) containing grafts of central (embryonic locus coeruleus, LC) or peripheral (juvenile adrenal medullary, AM, autologous superior cervical ganglionic, SCG) tissue were implanted unilaterally into rat lumbar spinal cord previously depleted of its NA content by 6-hydroxydopamine (6-OHDA) intraventricularly. A microdialysis probe was implanted in the spinal cord 3-4 months after transplantation, and extracellular levels of noradrenaline were monitored in freely moving animals during basal conditions and following administration of pharmacological or behavioural stimuli. Age-matched normal and lesioned animals both served as controls. Morphometric analyses were carried out on horizontal spinal sections processed for dopamine-beta-hydroxylase (DBH) immunocitochemistry, in order to assess lesion- or graft-induced changes in the density of spinal noradrenergic innervation, relative to the normal patterns. In lesioned animals, the entire spinal cord was virtually devoid of DBH-positive fibers, resulting in a dramatic 88% reduction in baseline NA, compared with that in controls, which did not change in response to the various stimuli. LC and SCG grafts reinstated approximately 80% and 50% of normal innervation density, respectively, but they differed strikingly in their release ability. Thus, LC grafts restored baseline NA levels up to 60% of those in controls, and responded with significantly increased NA release to KCl-induced depolarization, neuronal uptake blockade and handling. In contrast, very low NA levels and only poor and inconsistent responses to the various stimuli were observed in the SCG-grafted animals. In AM-grafted animals, spinal extracellular NA levels were restored up to 45% of those in controls, probably as a result of nonsynaptic, endocrine-like release, as grafted AM cells retained the chromaffine phenotype, showed no detectable fibre outgrowth and did not respond to any of the pharmacological or behavioural challenges. Thus, both a regulated, impulse-dependent, and a diffuse, paracrine-like, NA outflow may play roles in the recovery of lesion-induced sensory and/or motor impairments previously reported with these types of grafts following transplantation into the severed spinal cord.

Chronic elevation of amyloid precursor protein expression in the neocortex and hippocampus of rats with selective cholinergic lesions

Overexpression or aberrant processing of the beta-amyloid precursor protein (APP) and loss of cortical cholinergic function represent two hallmark pathological features of Alzheimer's disease, although it is still unclear whether these alterations take place independently or in an inter-related manner. In the present study, the possible relationships between altered APP expression and cholinergic hypofunction in the neocortex and hippocampus were addressed histologically following selective and complete (90-95%) removal of the basal forebrain cholinergic neurons by the 192 IgG-saporin immunotoxin, at a dose (5.0 microg, intraventricularly) producing profound and permanent cognitive deficits. Computer-aided densitometric analyses revealed, at 6 months post-lesion, a virtually complete loss of terminal cholinergic innervation in various neocortical and hippocampal regions (up to 80%), which correlated highly with the marked (up to 71%) increases in APP expression measured in the same territories. The present results indicate that the integrity of ascending basal forebrain cholinergic inputs to the neocortex and hippocampus may be required for the maintenance of physiological levels of APP expression in the same regions, thus providing a novel rationale for interventions aimed at restoring or enhancing cortical cholinergic neurotransmission.

Amelioration of spatial navigation and short-term memory deficits by grafts of foetal basal forebrain tissue placed into the hippocampus and cortex of rats with selective cholinergic lesions

Impairments in learning and memory, induced by surgical or excitotoxic lesions of the septo-hippocampal or basalo-cortical pathways, can be ameliorated by grafts of cholinergic-rich foetal basal forebrain tissue into the hippocampus and/or neocortex. However, the effects of such grafts have been only partial, which may be due to the non-specific nature of the lesioning procedures used in these studies, known to destroy both cholinergic and non-cholinergic neuronal projections. In the present study, we have explored the effects of cholinergic-rich grafts in rats subjected to selective cholinergic lesions, induced by intraventricular injections of the immunotoxin 192 IgG-saporin. This lesion, which selectively destroyed 85-95% of the cholinergic neurons in both the septal-diagonal band and nucleus basalis, produced a long-lasting, substantial impairment in both the acquisition of spatial reference memory in the Morris water maze task and delay-dependent short-term memory performance, as seen in a delayed matching-to-position test. Foetal cholinergic grafts (but not control grafts of cerebellar tissue) implanted at multiple sites into both the hippocampus and fronto-parietal neocortex, bilaterally, completely reversed the acquisition deficit in place navigation in the water maze, to an extent that greatly exceeded that previously seen in animals with non-selective lesions. Most notably, however, the impairment in short-term memory was only partially and inconsistently affected, and only at the longest delay times. The morphological analysis, performed at about 7 months after transplantation, showed that the grafts had re-established a close to normal cholinergic innervation in the initially denervated cortical and hippocampal territories. It is proposed that the differential effects of cholinergic-rich transplants on different aspects of cognitive performance may define intrinsic limitations to the functional capacity of the ectopically placed grafts, which may be due to incomplete integration of the grafted cholinergic neurons into functional regulatory circuitries normally available to the basal forebrain cholinergic system.

Extensive and permanent motoneuron loss in the rat lumbar spinal cord following neurotoxic lesion at birth: morphological evidence

The efficacy of the neurotoxic lectin volkensin to induce motoneuron loss in the lumbar spinal cord was investigated at different time-points following unilateral injection into the medial gastrocnemius muscle of newborn (postnatal day 1 (PD 1)) animals, using retrograde fluorescent neuron labelling and histochemical procedures to evaluate the extent of the toxin-induced depletion, in comparison with the effects produced by neonatal crushing of the sciatic nerve. The results show that very low doses (2.0 ng) of volkensin intramuscularly can produce extensive (about 90%) and long-lasting (up to at least 8 months post-lesion) motoneuronal loss in the lumbar spinal cord, whose magnitude is higher than that observed following mechanical injury of the developing peripheral nerve (50-60%). Volkensin-induced motoneuronal depletion may therefore represent a useful model for experimental studies aimed at functional cell replacement in the immature spinal cord.

Noradrenergic neurotransmission in the ventral spinal cord: basic characteristics and effects of denervating lesions, as studied in the awake rat by microdialysis

Extracellular levels of noradrenaline (NA) were measured in the ventral horn of the lumbar spinal cord in awake unrestrained rats using in vivo microdialysis coupled to a highly sensitive radioenzymatic assay. In normal animals, baseline NA output averaged 13.4 +/- 2.2 fmol/30 microliters. KCl (100 mM) or desipramine (5 microM) added to the perfusion fluid increased NA levels 11.2-fold and 2.2-fold, respectively, whereas neuronal impulse blockade by tetrodotoxin (1 microM) added in the presence of desipramine stimulation produced a 88% reduction of extracellular NA levels. Noradrenergic denervation of the spinal cord by either electrolytic destruction of the noradrenaline-containing axon terminals or intraventricular 6-hydroxydopamine produced, 3-4 weeks later, dramatic 84 and 91% reductions in baseline NA release associated to a marked loss of immunoreactive noradrenergic fibers throughout the spinal cord or caudal to the site of electrolytic damage and almost completely abolished responses to pharmacological manipulations. The results support the view that spinal extracellular NA levels are neuronally derived, also suggesting that noradrenergic neurotransmission in the ventral spinal cord largely (by at least 85%) depends on the integrity of descending brainstem afferents. The microdialysis technique, thus, appears to be a useful tool for future studies on strategies aimed at promoting reinnervation and functional recovery in the deafferented spinal cord.

Extensive reinnervation of the hippocampus by embryonic basal forebrain cholinergic neurons grafted into the septum of neonatal rats with selective cholinergic lesions

Reconstruction of the septohippocampal pathways by axons extending from embryonic cholinergic neuroblasts grafted into the neuron-depleted septum has been explored in the neonatal rat by using a novel lesioning and grafting protocol. Neonatal ablation of the basal forebrain cholinergic projection neurons, accompanied by extensive bilateral cholinergic denervation of the hippocampus and neocortex, was produced at postnatal day (PD) 4 by 192 immunoglobulin (IgG)-saporin intraventricularly. Four days later, cholinergic neuroblasts (from embryonic day 14 rats) were implanted bilaterally into the neuron-depleted septum by using a microtransplantation approach. The results show that homotopically implanted septal neurons survive and integrate well into the developing septal area, extending axons caudally along the myelinated fimbria-fornix and supracallosal pathways that are able to reach the appropriate targets in the denervated hippocampus and cingulate cortex as early as 4 weeks postgrafting. Moreover, the laminar innervation patterns established by the graft-derived axons closely resembled the normal ones and remained essentially unchanged up to at least 6 months, which was the longest postoperative time studied. The reinnervating fibers restored tissue choline acetyltransferase activity (up to 50% of normal) in the dorsal hippocampus and the parietooccipital cortex. Retrograde labeling with Fluoro-Gold from the host hippocampus combined with immunocytochemistry confirmed that most of the projecting neurons, indeed, were cholinergic. The results suggest that the graft-host interactions that are necessary for target-directed axon growth are present in the septohippocampal system during early postnatal maturation. Thus, the present approach may contribute to overcome the functional limitations inherent in the use of ectopically placed intrahippocampal transplants.

Effects of neonatal lesions of the basal forebrain cholinergic system by 192 immunoglobulin G-saporin: biochemical, behavioural and morphological characterization

Selective removal of the basal forebrain cholinergic neurons by the immunotoxin 192 immunoglobulin G-saporin has offered a new powerful tool for the study of the relationships between cholinergic dysfunction and cognitive impairments. In the present study the morphological and functional consequences of selective lesions of the basal forebrain cholinergic system during early postnatal development have been investigated following bilateral intraventricular injections of 192 immunoglobulin G-saporin to immature (four-day-old) rats. Administration of increasing doses (0.2-0.8 microgram) of the immunotoxin produced dose-dependent loss of cholinergic neurons in the septal/diagonal band area (up to 72-86%) and in the nucleus basalis magnocellularis (up to 91-93%), paralleled by marked reductions in choline acetyltransferase activity in the hippocampus and several cortical regions (73-84%). The parvalbumin-positive neurons in the septal/diagonal band area and the calbindin-positive Purkinje cells in the cerebellum were unaffected at all dose levels. Brain dopamine or noradrenaline levels were unaffected or increased by the immunotoxin treatment. At the optimal dose, 0.4 microgram, the toxin conjugate produced maximal cholinergic depletion without significant mortality. Higher doses (0.8, 1.2 and 1.6 micrograms) of toxin, on the other hand, proved to be lethal for most or all of the injected animals. When tested at three and eight months after the optimal dose, in spite of persisting cholinergic depletion, the noenatally lesioned animals showed no impairment in the water maze task or in locomotor activity and exploration as compared to normal controls, probably reflecting partial sparing of the cholinergic neurons by the neonatal immunotoxic lesion (above all in the vertical and horizontal limbs of the diagonal band area), and/or a greater degree of plasticity in the developing as compared to the mature cholinergic system. The place navigational performance of the neonatally lesioned animals in the water maze task was abolished by central muscarinic cholinergic receptor blockade (by atropine) or by a second immunotoxic lesion, which eliminated virtually all residual cholinergic neurons in the septal/diagonal band area and the nucleus basalis. Administration of 192 immunoglobulin G-saporin to similarly trained, but previously normal adult rats, produced similar cholinergic depletions but much less severe place navigation deficits, suggesting that preoperative training on the task may reduce the functional consequences of a subsequent cholinergic lesion. The results thus support the view that the basal forebrain cholinergic system may be implicated in the acquisition rather than retention of spatial memory in the water maze task.

Selective immunolesioning of the basal forebrain cholinergic system disrupts short-term memory in rats

Selective depletion of nerve growth factor receptor-bearing neurons in the basal forebrain cholinergic system nuclei by the immunotoxin 192 IgG-saporin offers a new and highly useful tool for the study of the role of the forebrain cholinergic system in cognitive functions. In the present study, we have tested the effects of 192 IpG-saporin in an operant delayed matching-to-position task which has previously been used to discriminate between delay-dependent learning impairments and delay-independent disturbances of non-mnemonic processes. Rats were first trained to criterion performance and then received intraventricular injections of 5 microg of 192 IgG-saporin 4 weeks prior to a second testing session. Rats with 192 IgG-saporin lesions displayed a significant delay-dependent decline in performance compared to normal controls, indicating a deficit in short-term memory. Administration of the muscarinic blocker scopolamine (0.5 mg/kg, i.p.) produced more pronounced impairment in the performance of the normal control rats across all delays, and induced further impairment also in animals with 192 IgG-saporin lesions. These effects were not observed following control injections of methyl scopolamine, suggesting that the impairment induced by scopolamine was due to the blockade of central muscarinic receptors. No improvement in performance was observed in either group following systemic treatment with the muscarinic cholinergic agonist arecoline (1.00 mg/kg). Biochemical and morphological analyses confirmed the selective and severe (>90-95%) depletion of cholinergic neurons throughout the septal-diagonal band area and the nucleus basalis region by the intraventricular 192 IgG-saporin treatment. Although the immunotoxin was observed to produce additional damage to the cerebellar Purkinje cells, no gross motor abnormalities were observed that could contribute to the effects on accuracy in the task used here. In conclusion, the results show that selective combined lesions of the basal forebrain cholinergic neurons in the septal-diagonal band area and nucleus basalis produce long-lasting impairments in short-term memory, thus providing further support for a role of this system in cognitive functions.

Immunolesioning of basal forebrain cholinergic neurons facilitates hippocampal kindling and perturbs neurotrophin messenger RNA regulation

The immunotoxin 192 IgG-saporin induces an efficient and specific lesion of low-affinity nerve growth factor receptor-bearing cholinergic neurons in the basal forebrain. Intraventricular injection of 192 IgG-saporin, which caused a complete loss of cholinergic afferents to the hippocampus and neocortex and a partial denervation of amygdala and piriform cortex, was found to markedly facilitate the initial stages of seizure development in hippocampal kindling. In contrast, the progression of kindling process from focal to generalized seizures was not affected. In situ hybridization demonstrated that basal levels of brain-derived neutrotrophic factor messenger RNA in the hippocampal formation and piriform cortex were significantly decreased by the lesion, which also attenuated the seizure-induced increase of brain-derived neurotrophic factor messenger RNA expression in the hippocampus and frontal cortex. In the dentate gyrus, the 192 IgG-saporin lesion selectively reduced the upregulation of messenger RNAs for brain-derived neurotrophic factor exons I and III after a generalized seizure, whereas the increase of exon II messenger RNA was unchanged. The lesion abolished the seizure-evoked increase of nerve growth factor and TrkC messenger RNA levels and decrease of neutrophin-3 messenger RNA expression in dentate granule cells, while TrkB messenger RNA levels were not affected. We conclude that the basal forebrain cholinergic system (1) suppresses kindling epileptogenesis in the hippocampus, and (2) enhances both basal and seizure-evoked brain-derived neurotrophic factor synthesis in the hippocampal formation and some cortical areas through a specific pattern of activation of promoters within the brain-derived neurotrophic factor gene.

Branching serotonergic and non-serotonergic projections from caudal brainstem to the medial preoptic area and the lumbar spinal cord, in the rat

The distribution and the chemical identity of retrogradely single and double labeled neurons in the caudal raphe nuclei were analyzed in the rat following injection of two fluorescent tracers into the medial preoptic area and the ventral/intermediate grey of the lumbar spinal cord, and serotonin immunocytochemistry. The results suggest that (1) neurons in the caudal raphe nuclei exhibit highly collateralized axons, able to simultaneously innervate rostrally- and caudally-located targets; (2) a large proportion (40-50%) of the raphe-spinal projection does not contain serotonin, which by contrast is present in more than 70% of the neurons projecting to the medial preoptic area; (3) only a small fraction of the observed collateralized projection is serotonergic. Thus, multiple transmitter systems are likely to be involved in the diffuse ascending and descending influence arising from these nuclei.

Activation of metabotropic glutamate receptors protects cultured neurons against apoptosis induced by beta-amyloid peptide

Prolonged exposure of cultured cortical cells or cultured cerebellar granule cells to the residue 25-35 fragment of beta-amyloid peptide (beta AP), beta AP(25-35), induced neuronal apoptosis, as revealed by morphological analysis, fluorescent chromatin staining, and immunodetection of oligonucleosomes released from the nucleus into the cytoplasm. beta AP(25-35)-induced apoptosis was insensitive to ionotropic glutamate receptor antagonists but was substantially attenuated by the metabotropic glutamate receptor (mGluR) agonist (1S,3R)-1-aminocyclopentane-1,3-dicarboxylic acid. The neuroprotective action of (1S,3R)-1-aminocyclopentane-1,3-dicarboxylic acid was antagonized by (RS)-alpha-methyl-4-carboxyphenylglycine and was mimicked by (2S,1'R,2'R,3'R)-2-(2,3-dicarboxycyclopropyl)glycine (a selective agonist of mGluR2 and -3 subtypes) and by L-2-amino-4-phosphobutanoate and L-serine-O-phosphate (selective agonists of mGluR4, -6, and -7 subtypes). However, whereas all of these drugs behaved as neuroprotectants in cultured cortical cells, only L-2-amino-4-phosphobutanoate and L-serine-O-phosphate [and not (2S,1'R,2'R,3'R)-2-(2,3-dicarboxycyclopropyl)glycine] reduced beta AP(25-35)-induced apoptosis in cultured cerebellar granule cells. The neuroprotective activity of mGluR agonists may be related to their ability to inhibit membrane Ca2+ conductance, because drugs that block voltage-sensitive Ca2+ channels, such as nimodipine or Co2+, could also attenuate beta AP(25-35)-induced apoptosis.

Selective lesioning of the basal forebrain cholinergic system by intraventricular 192 IgG-saporin: behavioural, biochemical and stereological studies in the rat

The elucidation of the functional role of the basal forebrain cholinergic system will require access to a highly specific and efficient cholinergic neurotoxin. Recently, selective depletion of the nerve growth factor (NGF) receptor-bearing cholinergic neurons in the rat basal forebrain and a dramatic loss of cholinergic innervation in the related cortical regions have been obtained following intraventricular injection of a newly introduced immunotoxin, 192 IgG-saporin. Here we extend these initial findings and report that administration of increasing doses (1.25, 2.5, 5.0 or 10 micrograms) of the 192 IgG-saporin conjugate into the lateral ventricles of adult rats induced dose-dependent impairments in the water maze task and passive avoidance retention, but only weak and inconsistent effects on locomotor activity. These behavioural changes were paralleled by a reduction in choline acetyltransferase activity in hippocampus and several cortical areas (up to 97%) and selective depletions of NGF receptor-positive cholinergic neurons in the septal-diagonal band area and nucleus basalis magnocellularis (up to 99%). By contrast, the non-cholinergic parvalbumin-containing neurons in the septum were completely spared, and other cholinergic projection systems (such as in the striatum, thalamus, brainstem and spinal cord) were unaffected even at the highest dose. The observed changes in the water maze and passive avoidance tasks, as well as the cholinergic cell loss, were maintained up to at least 8 months following the intraventricular injection of a single dose (5 micrograms) of the immunotoxin. The results confirm the usefulness of the 192 IgG-saporin toxin for selective and profound lesions of the basal forebrain cholinergic neurons and provide further support for a role of the basal forebrain cholinergic system in cognitive functions.

Inhibition of proopiomelanocortin expression by an oligodeoxynucleotide complementary to beta-endorphin mRNA

Gene expression in mammalian cells can be suppressed by oligonucleotides complementary to the target mRNA. This strategy was explored as a means of arresting translation of the prohormone precursor proopiomelanocortin (POMC), used as a model system of peptide messengers that are synthesized and released from endocrine and neuronal cells. The synthesis of the POMC-derived peptides adrenocorticotropin (ACTH) and beta-endorphin (beta-END) was markedly reduced by an oligodeoxynucleotide (ODN) complementary to a region of beta-END mRNA in AtT-20 cells, which retain many of the differentiated phenotypes of corticotrophs; this treatment did not affect the steady-state levels of POMC mRNA. Antisense ODN was stable in cell culture medium for 24 h, and cellular uptake was low (approximately 2.5% of the added ODN); however, the intracellular levels of the ODN were sufficient to form a ribonuclease-resistant duplex with complementary cellular mRNA. Addition of ODN to the cell culture did not affect the cellular levels of chromogranin A-(264-314)/pancreastatin or cell viability and proliferation, as evidenced by bromodeoxyuridine incorporation and ornithine decarboxylase activity. Microinfusion of the antisense ODN in the rat hypothalamic arcuate nucleus, where the majority of POMC-positive brain perikarya are located, significantly reduced ACTH- and beta-END-immunopositive neurons, and antisense ODN-treated rats showed substantially less of the grooming behavior usually observed in a novel environment.

Amphetamine induces excess release of striatal acetylcholine in vivo that is independent of nigrostriatal dopamine

The effect of amphetamine on striatal acetylcholine (ACh) release was studied by an in vivo intrastriatal microdialysis technique. Although we expected systemic amphetamine to inhibit baseline striatal ACh release, the opposite was found. In addition, we found that the amphetamine-induced striatal ACh release did not depend on nigrostriatal DA since 6-hydroxydopamine (6-OHDA) lesions had no effect on amphetamine-induced ACh release. Local intrastriatal injection of amphetamine via the microdialysis probe had no effect on striatal ACh release even when the probe was located more laterally in striatum to take advantage of the medial to lateral gradient of striatal ACh and D2 receptors. The hypothesis that amphetamine increased extracellular striatal ACh by increasing the release of biogenic amines besides dopamine was tested by pharmacological manipulations designed to specifically increase local striatal norepinephrine or serotonin levels. The serotonergic and noradrenergic manipulations had no effect on striatal ACh levels. These results indicate that amphetamine-induced release of ACh in striatum is mediated via distal brain regions that are functionally connected with the striatum.

Basal forebrain grafts in the hippocampus and neocortex: regulation of acetylcholine release

The regulation of acetylcholine (ACh) release from cholinergic neurons transplanted to the hippocampus or neocortex was studied by microdialysis in awake rats. Fetal basal forebrain tissue was implanted as a cell suspension or solid graft into the fimbria-fornix-lesioned hippocampus, or as a cell suspension into the frontal cortex after excitotoxic lesion of the nucleus basalis. Several months after transplantation, microdialysis probes were implanted in areas of the hippocampus or frontal cortex reinnervated by the grafts. The grafts restored lesion-induced deficits in steady-state ACh release up to normal or above normal levels in both hippocampus and frontal cortex. The responses to KCl and tetrodotoxin suggested that the ACh release exhibited normal firing-dependent properties. By applying various behaviorally arousing stimuli that normally activate the basal forebrain projection systems, we wished to investigate the functional integration of the grafts in the host brain. In the hippocampus, sensory stimulation, immobilization stress and motor activity all resulted in increased release of graft-derived ACh amounting to 25-65% of the normal response. Variations in ACh levels during the day-night cycle was, however, not observed in the grafted rats. In the frontal cortex, immobilization enhanced the graft-derived ACh release (60% of normal response), whereas the response to sensory stimulation did not reach significance. Since the activity of the normal basal forebrain projection systems is under influence of monoaminergic brainstem afferents, we investigated the effects of systemic administration of amphetamine or apomorphine on ACh release in the hippocampus. Both drugs produced increases in graft-derived ACh release although the response was variable and less pronounced than normal. In conclusion, the graft-derived ACh release was affected by behavioral manipulations and catecholaminergic drugs that normally modify cholinergic septo-hippocampal and basalo-cortical activity. This strongly suggests a high degree of functional integration of the graft in the host brain allowing for a regulated release of transmitter that can be adjusted during ongoing behavior.

Functional activity of intrahippocampal septal grafts is regulated by catecholaminergic host afferents as studied by microdialysis of acetylcholine

Previous microdialysis experiments have shown that acetylcholine (ACh) release from septal grafts in the hippocampus of awake rats is influenced by the behaviour of the animals, which strongly suggests that the host brain can exert a regulatory control over the activity of the grafted neurons. Since the activity of the normal septo-hippocampal cholinergic system is likely to be regulated, in part, by brainstem catecholaminergic afferents, we wished to study the effect of catecholaminergic drugs on ACh release in the hippocampus reinnervated by septal grafts. Rats were subjected to a unilateral aspirative fimbria-fornix (FF) transection and grafted with tissue from the fetal septal-diagonal band area, either as a cell suspension injection into the depth of the hippocampus or as a solid implant in the FF lesion cavity. Microdialysis of ACh release was carried out 17-20 months after transplantation in awake, freely-moving animals. The reduction in steady-state ACh overflow induced by the FF lesion (-81%) was restored to normal or above normal levels in rats with either solid or suspension grafts. In normal rats, systemic administration of apomorphine (2.0 mg/kg, s.c.) or amphetamine (2.5 mg/kg, i.p.) caused a 3.7 (+189%) or 7.8 (+301%) pmol/15 min increase in ACh overflow compared to the previous baseline level, respectively. The drug-induced increases in ACh levels in the FF-lesioned controls was substantially lower than normal (86-89% reduction). Both apomorphine and amphetamine resulted in an approximately two-fold increase in hippocampal ACh release in rats with suspension grafts. These responses were significantly increased over those seen in rats with FF lesions only, but they tended to be lower and more variable than normal. Rats with solid septal grafts responded significantly stronger than FF lesion controls to amphetamine with two-fold increased ACh overflow, whereas the response to apomorphine was less clear-cut. Pretreatment with the catecholamine synthesis blocker alpha-methyl-p-tyrosine (AMPT; 200 mg/kg x 3) did not affect steady-state or apomorphine-stimulated release of ACh in any of the groups, whereas the effect of amphetamine was abolished in both normal and grafted rats. The results suggest that ACh release derived from septal grafts in the hippocampus, similar to the normal septo-hippocampal system, can be affected by manipulations of the host catecholaminergic systems. This mechanism may, at least in part, underlie the ability of the host brain to influence and control the activity of grafted cholinergic neurons.

Compensatory changes of in vivo acetylcholine and noradrenaline release in the hippocampus after partial deafferentation, as monitored by microdialysis

Lesions of the fimbria-fornix pathways are known to induce a partial cholinergic and noradrenergic denervation of the hippocampal formation, which is followed by a slow and protracted collateral sprouting by the spared afferents. Using the intracerebral microdialysis technique, compensatory changes in extracellular levels of acetylcholine (ACh) and noradrenaline (NA) have been monitored over time in the partially denervated hippocampus of awake unrestrained rats subjected to an unilateral fimbria-fornix (FF) transection. One week after the lesion, baseline ACh output was reduced by 90% and 80% in the dorsal and ventral hippocampus, respectively, and it remained depressed still by 6 months after lesion. KCl-evoked and atropine-stimulated ACh efflux were equally reduced by 1 week after lesion, remained depressed at 3 months, but showed a significant recovery by 6 months post-lesion. Tissue choline acetyltransferase (ChAT) activity levels, initially reduced by 92% and 86%, in the dorsal and ventral hippocampus, respectively, recovered significantly by 3 months and remained unchanged at 6 months. Baseline NA output was significantly reduced (-80%) in the dorsal hippocampus by 1 week after the lesion and showed a partial recovery over time (to 50% of normal), whereas the ventral part was not significantly affected by the FF lesion. The significant FF lesion-induced reduction in KCl- or desipramine (DMI)-stimulated NA release observed in the dorsal hippocampus at 1 week after the lesion remained unchanged during the subsequent months. By contrast, in the ventral hippocampus, the initial 65-70% reduction in KCl- and DMI-stimulated NA release significantly recovered to normal levels within 3 months post-lesion. The NA tissue levels were significantly reduced by 4 weeks after lesion, in the dorsal hippocampus and did not show any significant recovery over time. In the ventral hippocampus, these levels were significantly reduced only at 4 weeks. Transmitter turnover, expressed as the ratio between dialysate levels and tissue ChAT or NA content, showed a 3-fold increase in the dorsal hippocampus at 4 weeks after lesion, but not at later time points. This indicates that the spared noradrenergic and cholinergic afferents respond to the partial denervation by a transient increase in transmitter turnover, evident as early as 4 weeks post-lesion in the region of maximal denervation. This was followed by a long-term increase in evoked transmitter release which may result from a slowly progressing compensatory sprouting of the spared afferents.

Regulation of neurotrophin and trkA, trkB and trkC tyrosine kinase receptor messenger RNA expression in kindling

Levels of messenger RNA for nerve growth factor, brain-derived neurotrophic factor, neurotrophin-3, and the tyrosine kinase receptors trkA, trkB and trkC have been studied using in situ hybridization in the rat brain 2 h and four weeks after kindling-induced seizures. Epileptiform activity evoked by hippocampal stimulation and exceeding 70 s lead to a concomitant and transient increase of brain- derived neurotrophic factor, nerve growth factor, trkB and trkC messenger RNA expression in dentate granule cells after both focal and generalized seizures. Brain-derived neurotrophic factor messenger RNA levels were also increased bilaterally in the CA1-CA3 regions, amygdala and the piriform, entorhinal, perirhinal, retrosplenial and temporal cortices after generalized seizures. The magnitude of the increases was similar throughout the development of kindling and in the fully kindled brain. No changes of trkA messenger RNA were observed. In amygdalar kindling, elevated brain-derived neurotrophic factor messenger RNA levels developed more rapidly in the amygdala-piriform cortex than after stimulation in the hippocampus but changes in the hippocampal formation were only seen in few animals. Intraventricular 6-hydroxydopamine or a bilateral fimbria-fornix lesion did not alter basal expression or seizure-evoked changes in messenger RNA levels for neurotrophins or trk receptors but increased the number of animals exhibiting elevated levels after the first stimulation, probably due to a prolongation of seizure activity. Both in sham-operated and fimbria-fornix-lesioned rats seizure activity caused a marked reduction of neurotrophin-3 messenger RNA levels in dentate granule cells. The results indicate that activation of the brain-derived neurotrophic factor gene, at least in dentate granule cells, is an "all-or-none" type of response and dependent on the duration but not the severity of seizures or the stage of kindling epileptogenesis. Changes in brain-derived neurotrophic factor, nerve growth factor, neurotrophin-3 and trkB and trkC were observed concomitantly in the dentate gyrus, which suggests that seizure activity sets in motion a cascade of genomic events possibly mediated via a common mechanism. Since altered messenger RNA levels outside hippocampus were detected only for brain-derived neurotrophic factor, neurotrophin and trk gene expression in these regions seems to be regulated differently.

Spatial learning impairments in rats with selective immunolesion of the forebrain cholinergic system

A monoclonal antibody to the low-affinity NGF receptor, 192 IgG, coupled to a cytotoxin, saporin, was recently introduced as an efficient selective neurotoxin for the NGFr-bearing cholinergic neurones in the rat basal forebrain. In the present study we report that an intracerebroventricular injection of this 192 IgG-saporin conjugate induces a severe, long-lasting spatial learning impairment, as assessed in the Morris water-maze task. This behavioural impairment was associated with 65-90% depletion of choline acetyltransferase activity (ChAT) in the hippocampus and cortex. ChAT activity associated with other cholinergic neurone systems in the brain (striatum, mesencephalon, spinal cord), was left virtually unaffected. This new immunotoxin holds great promise as a tool for selective and efficient lesions of the forebrain cholinergic system in functional and behavioural studies.

Acetylcholine release in the hippocampus: regulation by monoaminergic afferents as assessed by in vivo microdialysis

The role of monoamines in the functional regulation of the septo-hippocampal cholinergic system was studied using in vivo microdialysis of acetylcholine (ACh) release in the hippocampus of awake unrestrained rats. Systemic administration of the dopamine receptor agonist apomorphine (2.0 mg/kg) resulted in a 170% increase in hippocampal ACh overflow. Similarly the catecholamine-releasing agent amphetamine (2.5 mg/kg) produced a 400% increase in ACh overflow. The effect induced by amphetamine, but not that of apomorphine, was blocked in animals pretreated with the tyrosine hydroxylase inhibitor alpha-methyl-p-tyrosine (AMPT). The effect of amphetamine on ACh release was reduced by 75% after a 6-hydroxydopamine (6-OHDA) lesion of the ventral tegmental area (VTA) but was not affected by 6-OHDA lesions of the noradrenergic dorsal and ventral bundles. However, baseline ACh overflow was increased by 130% by the dorsal and ventral bundle lesions. The serotonin-releasing agent p-chloroamphetamine (2.5 mg/kg) produced a 160% increase in hippocampal ACh release, and this effect was enhanced after a 5,7-dihydroxytryptamine (5,7-DHT) lesion of the serotonin projection system. The results show that surgical or pharmacological manipulations of the ascending brainstem monoaminergic systems, which innervate wide areas of the forebrain, including the septum and the hippocampal formation, have pronounced effects on septo-hippocampal cholinergic activity. Thus, the present data provide support for the view that information regarding behavioral state and arousal is conveyed to the septo-hippocampal system via ascending monoaminergic systems.

Neurons in raphe nuclei pontis and magnus have branching axons that project to medial preoptic area and cervical spinal cord. A fluorescent retrograde double labeling study in the rat

In this study, we utilized a double retrograde axonal tracing technique to investigate the possible existence of collateralized axonal projections from raphe nuclei 'pontis' and 'magnus' to both medial preoptic area (MPA) and cervical spinal cord (C1-C2). Following microinjections of fluorescent tracers Fast blue (FB) and Diamidino yellow (DY) within MPA and C1-C2, substantial numbers of FB and DY single-labeled neurons, as well as FB-DY double-labeled neurons have been found within raphe nuclei 'pontis' and 'magnus'.

Branching projections from subcoeruleus area neurons to medial preoptic area and cervical spinal cord revealed by double retrograde neuronal labeling

In this study we utilized a double retrograde axonal tracing technique to investigate the possible existence of collateralized axonal projections of subcoeruleus area neurons to both 'medial preoptic area (MPA) and cervical (C1-C3) spinal cord'. Following microinjections of fluorescent tracers (Fast blue (FB) and Diamidino yellow (DY) within MPA and C1-C3, substantial numbers of FB and DY single-labeled neurons as well as FB-DY double-labeled branched neurons have been found within subcoeruleus area.

Role of the ventromedial hypothalamus in the regulation of adenohypophyseal immunoreactive dynorphin in the rat

In this study, we have examined the role of the dorsomedial (DMH), ventromedial (VMH) and arcuate (ARH) nuclei of the hypothalamus in the control of hypothalamic and pituitary immunoreactive (ir) dynorphin (Dyn) A and ir-Dyn B in the rat, by evaluating the effect of discrete, bilateral radiofrequency lesions in these structures. Lesions limited to the VMH reduced the content of ir-Dyn in the anterior pituitary but not in the neurointermediate lobe or in the hypothalamus. Gel chromatographic analysis of anterior pituitary extracts confirmed that ir-Dyn is mainly associated with high molecular weight forms containing Dyn A and Dyn B in their sequence. Anterior pituitary extracts of VMH-lesioned rats displayed a clearly lower proportion of these forms. Destruction of the DMH affected only the hypothalamic content of ir-Dyn; ablation of the ARH did not cause any significant change. Our results suggest that ablation of the VMH may disrupt critical neuronal connections to the median eminence originating in this nucleus or crossing it and participating in control of the adenohypophyseal pool of ir-Dyn.

Branching axons from subcoeruleus area project to the nucleus raphe pontis and hypothalamic zona incerta, as studied with the double fluorescent retrograde tracing technique

In this study we utilized a double retrograde axonal tracing technique to investigate the possible existence of collateralized axonal projections of subcoeruleus area neurons to both raphe pontis nucleus and hypothalamic zona incerta. Following microinjections of fluorescent tracers (Fast blue (FB) and Diamidino yellow (DY] within raphe pontis and zone incerta, substantial numbers of double-labeled branched neurons have been found within the subcoeruleus area.

Immunoreactive dynorphin-like material in rat pituitary after ovariectomy

Ovariectomy caused a significant increase of immunoreactive dynorphin-like material (IR-DYAN) in the anterior pituitary lobe of intact as well as of medial basal hypothalamus-lesioned rats. No change of IR-DYAN was observed in the neurointermediate lobe of the gland or in the hypothalamus. Estradiol benzoate reversed the increase of anterior pituitary IR-DYAN induced by ovariectomy and caused a reduction in sham-ovariectomized rats.

[Projections to the supraoptic and paraventricular nuclei studied in the rat by means of retrograde fluorescent tracers (fast blue, nuclear yellow)]

Afferent projections into rat supraoptic nucleus (SO) and paraventricular nucleus (PVH) were studied with two fluorescent retrograde neuronal tracers: Nuclear Yellow (NY) and Fast Blue (FB). FB labeled cells were found into paraolfactory area (ACB), basolateral amygdaloid nucleus (ABL), lateral hypothalamus (LH), ventromedial nucleus (VMH) and dorsomedial hypothalamic)nucleus (DMH), tegmental nucleus of the pons (TPO). NY labeled cells were found into posterior hypothalamus (PH), dorsal raphe nucleus (DR) and tegmental nucleus of the pons (TPO). Few double-labeled neurons were found into TPO. The finding of double labeled neurons in the TPO is of particular interest. This latter nucleus is classically connected to the cerebellum trough the olivary nucleus and can serve as liaison for transmission of messages, e.g. vestibular, regarding spacial position variations. We can conclude affirming that quite a lot of informations of diverse nature converges on the SO and PVH nuclei that by efferent pathways may regulate hypothalamic neurosecretion, thus modifying the animal's behaviour response to different external stimuli.