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1.
Curr Aging Sci ; 1(1): 42-50, 2008 Mar.
Article in English | MEDLINE | ID: mdl-20021371

ABSTRACT

UNLABELLED: Hypopituitarism (HYPO) is a rare and under-investigated pathology in the elderly. AIM: to review our case records of patients > or =65 yrs with first diagnosis of anterior global hypopituitarism, in order to evaluate presentation symptoms, etiology, biochemical and hormonal pictures, pituitary morphology, and efficacy of therapy. PATIENTS: 15 patients (65-82 yrs) were studied: in 11 (73%) HYPO was secondary to pituitary macroadenoma (non-secreting in 10 and GH-secreting in 1); in 3 it was associated to empty sella, and in 1 to pituitary hypoplasia. RESULTS: major presenting symptoms were visual-field defects and asthenia (40%) but also memory and/or gait impairment and nausea (30%) and depression (20%) were significantly observed. Dyslipidemia (73%), anemia (20%) and severe hyponatremia (13%) were found. After starting substitutive therapy and clinical improvement, 10 patients with macroadenoma underwent uneventful neurosurgery, which improved visual alterations but not pituitary function. Immunohistochemistry showed positivity for FSH in one patient and for GH in one patient. Six out of the eight patients with a post-surgical tumor remnant required treatment (surgery/radiotherapy/somatostatin analogue treatment in the acromegalic patient). CONCLUSIONS: The diagnosis of HYPO is often delayed in the elderly, since symptoms may be ascribed to aging and associated comorbidities. In our series, most of the aspecific symptoms were retrospectively addressed to HYPO since their resolution/improvement with replacement therapy. The prevalent cause of HYPO remains non-functioning pituitary macroadenomas. Hyponatremia can be a life-threatening presenting symptom. Symptoms considered apparently aspecific in the elderly should be investigated in order to possibly diagnose an important treatable disorder as HYPO.


Subject(s)
Aging , Hypopituitarism , Age Factors , Aged , Aged, 80 and over , Biomarkers/blood , Chemotherapy, Adjuvant , Diagnostic Techniques, Ophthalmological , Empty Sella Syndrome/complications , Female , Hormones/blood , Humans , Hypopituitarism/blood , Hypopituitarism/diagnosis , Hypopituitarism/etiology , Hypopituitarism/therapy , Magnetic Resonance Imaging , Male , Neurosurgery , Pituitary Function Tests , Pituitary Gland/metabolism , Pituitary Gland/pathology , Pituitary Neoplasms/complications , Predictive Value of Tests , Radiotherapy, Adjuvant , Retrospective Studies , Risk Factors , Tomography, X-Ray Computed , Treatment Outcome
2.
J Endocrinol Invest ; 30(7): 603-9, 2007.
Article in English | MEDLINE | ID: mdl-17848845

ABSTRACT

TSH-secreting pituitary adenomas (TSH-omas) are a rare cause of hyperthyroidism in clinical practice. As their diagnosis is often delayed, these tumors are mostly diagnosed as macroadenomas, preventing an effective and radical cure and leading to serious local and systemic comorbidities. In addition to neurosurgery, medical therapy with the effective and tolerable SS analogs is a fundamental tool for the treatment of TSHomas. We report 3 cases of TSH-macroadenomas which displayed different clinical presentations. All patients showed increased free-thyroid hormone levels with inappropriately normal (2 patients) or high (1 patient) TSH levels. Magnetic resonance imaging (MRI)/computed tomography (CT) evidenced a pituitary macroadenoma and octreoscan was positive in all patients. In the 2 patients who underwent neurosurgery, hormonal hypersecretion by the tumor normalized. Histology showed nuclear pleomorphism and fibrosis, whereas immunohistochemistry showed positivity for TSH and, in a lesser amount, for FSH. In one of these patient (case 1), however, the presence of a tumor remnant inside the left cavernous sinus prompted us, in accordance with the patient, to start therapy with octreotide- long-acting release. As the third patient had a cardiac comorbidity which contraindicated neurosurgery, he underwent satisfactory treatment with long-acting SS analogs alone which normalized thyroid hormone levels. In this case, previous treatment with amiodarone confused and delayed the correct diagnosis of TSH-oma. As a result of improved laboratory and morphological techniques, TSH-omas should currently be diagnosed in early stages, thus enabling most patients to be managed satisfactorily through a combined approach.


Subject(s)
Adenoma/diagnosis , Pituitary Neoplasms/diagnosis , Thyrotrophs/pathology , Adenoma/pathology , Adenoma/therapy , Aged , Aged, 80 and over , Humans , Male , Middle Aged , Pituitary Neoplasms/pathology , Pituitary Neoplasms/therapy
3.
Minerva Endocrinol ; 30(2): 95-9, 2005 Jun.
Article in Italian | MEDLINE | ID: mdl-15988405

ABSTRACT

A 74 year-old man was admitted to the hospital for heart failure and atrial fibrillation episodes. He had been irregularly treated for hyperthyroidism during the previous 3 years, with poor control. Thyroid function evaluation showed secondary hyperthyroidism, with high free thyroid hormone levels and TSH inappropriately in the high-normal range (4.2 mU/ml), only slightly responsive to TRH-stimulation (6 microU/ml). Alpha-subunits were hyper-responsive to TRH stimulation (+123%). Thyroid autoimmunity tests were negative and ultrasonography evidenced a diffusely enlarged gland. Magnetic resonance (MR) imaging of the pituitary showed a macroadenoma. The patient underwent transphenoidal adenomectomy, and immunohistochemistry confirmed the diagnosis of a TSH-secreting pituitary macroadenoma. A moderate secondary hyperthyroidism was still present and a new MR evidenced residual disease, involving the right cavernous sinus. A (111)In-octreoscan revealed an increased captation in this area. The patient was treated with octreotide-Lar (20 mg/monthly), which normalized FT3, FT4 and TSH levels already after 3 months of therapy. This effect is still maintained at 42 months of treatment. MR imaging showed a reduction in the residual lesion after 18 months (>50% in comparison with postsurgical MR) and a further decrease after 36 months of treatment). This suggests that the antiproliferative effect on the adenomatous cells is progressive and continues over time. This patients did not receive radiotherapy, so this action is entirely due to the medical treatment. No significant side effects developed and the patient's compliance was good. He has not had further arrhythmic episodes.


Subject(s)
Adenoma/drug therapy , Antineoplastic Agents, Hormonal/therapeutic use , Hyperthyroidism/drug therapy , Hyperthyroidism/etiology , Octreotide/therapeutic use , Pituitary Neoplasms/drug therapy , Thyrotropin/metabolism , Adenoma/blood , Adenoma/diagnosis , Adenoma/surgery , Aged , Antineoplastic Agents, Hormonal/administration & dosage , Humans , Hyperthyroidism/diagnosis , Hyperthyroidism/surgery , Male , Octreotide/administration & dosage , Pituitary Neoplasms/blood , Pituitary Neoplasms/diagnosis , Pituitary Neoplasms/surgery , Thyroid Hormones/blood , Treatment Outcome
4.
J Neurosurg Sci ; 45(1): 53-7, 2001 Mar.
Article in English | MEDLINE | ID: mdl-11466509

ABSTRACT

Spinal subarachnoid bleeding of unknown etiology is extremely rare. It has been suggested that these lesions have to be divided into two subtypes with different behaviour and prognosis according to their location around the spinal cord. The dorsally located bleeding would invariably cause severe spinal cord compression while the ventral lesions would have a very benign course in the absence of remarkable neurological deficit. We observed two patients with spontaneous spinal subarachnoid bleeding of unknown etiology. In both cases the disease was revealed by the sudden onset of severe back pain without subsequent signs of spinal cord compression. In one case the bleeding was ventral to the spinal cord while in the other it was located dorsally. The patients were evaluated with panspinal MRI and selective spinal angiography. They were treated conservatively and follow-up examinations at 18 and 24 months show they are neurologically intact in the absence of rebleeding episodes. We think the diagnosis of spontaneous subarachnoid bleeding of unknown etiology cannot be achieved without a panspinal MRI and a selective angiography have ruled out any other causes. We suggest their incidence is more prevalent than reported due to the difficulty/reluctance to employ MR in the presence of only minor symptoms. Our cases also show that these lesions may have a benign course independently from their location around the spinal cord.


Subject(s)
Spinal Cord/blood supply , Spinal Cord/pathology , Subarachnoid Hemorrhage/etiology , Subarachnoid Hemorrhage/pathology , Hematoma/pathology , Humans , Lumbar Vertebrae , Magnetic Resonance Imaging , Male , Middle Aged , Thoracic Vertebrae
5.
J Am Podiatr Med Assoc ; 89(11-12): 560-70, 1999.
Article in English | MEDLINE | ID: mdl-10609458

ABSTRACT

The efficacy of the transverse plantar incisional approach for the treatment of recalcitrant heel spur syndrome or plantar fasciitis was investigated by evaluating cases of this procedure performed by the authors from 1991 to 1998. Patient records were reviewed for conservative treatment rendered prior to surgical intervention as well as for the perioperative course of the patient. All patients were asked to complete questionnaires regarding their heel spur syndrome or plantar fasciitis and their opinion of both the conservative and the surgical treatments received.


Subject(s)
Exostoses/surgery , Fasciitis/surgery , Foot Diseases/surgery , Orthopedic Procedures/methods , Adult , Aged , Direct Service Costs , Female , Heel/surgery , Humans , Male , Middle Aged , Orthopedic Procedures/economics , Retrospective Studies , Surveys and Questionnaires
6.
J Spinal Disord ; 12(6): 534-6, 1999 Dec.
Article in English | MEDLINE | ID: mdl-10598998

ABSTRACT

Posttraumatic spinal epidural hematoma is an unusual pathology. The authors report the case of a 64-year-old woman who experienced thoracic epidural hematoma during a session of spinal manipulation therapy (SMT). In the literature, such an event has been reported previously only twice. This case represents the first spinal epidural hematoma occurring after a chiropractic manipulation in the lumbar region. Surgical evacuation of the spinal hematoma resulted in complete recovery in the patient. Complications of SMT are reviewed, and the etiology and features of spinal epidural hematoma are discussed.


Subject(s)
Hematoma, Epidural, Cranial/etiology , Manipulation, Spinal/adverse effects , Thoracic Vertebrae , Female , Hematoma, Epidural, Cranial/surgery , Humans , Magnetic Resonance Imaging , Middle Aged , Spinal Cord Compression/etiology
7.
Br J Pharmacol ; 126(3): 607-12, 1999 Feb.
Article in English | MEDLINE | ID: mdl-10188970

ABSTRACT

The releases of [3H]5-hydroxytryptamine ([3H]5-HT) and of endogenous glutamic acid and their modulation through presynaptic h5-HT1B autoreceptors and h5-HT1D heteroreceptors have been investigated in synaptosomal preparations from fresh neocortical samples obtained from patients undergoing neurosurgery. The inhibition by 5-HT of the K+ (15 mM)-evoked overflow of [3H]5-HT was antagonized by the 5-HT1B/5-HT1D receptor ligand GR 127935, which was ineffective on its own; this drug was previously found to behave as a full agonist at the h5-HT1D heteroreceptor regulating glutamate release. The recently proposed selective h5-HT1B receptor ligand SB-224289 also prevented the effect of 5-HT at the autoreceptor, being inactive on its own; in contrast, SB-224289, at 1 microM, was unable to interact with the h5-HT1D heteroreceptor. The inhibitory effect of 5-HT on the K+-evoked overflow of glutamate was antagonized by the h5-HT1D receptor ligand BRL-15572; added in the absence of 5-HT the compound was without effect. BRL-15572 (1 microM) was unable to modify the effect of 5-HT at the autoreceptor regulating [3H]5-HT release. The selective 5-HT1A receptor antagonist (+)-WAY 100135, previously found to be an agonist at the h5-HT1D heteroreceptor regulating glutamate release, could not interact with the h5-HT1B autoreceptor when added at 1 microM. It is concluded that native h5-HT1B and h5-HT1D receptors exhibit a hitherto unexpected pharmacological diversity.


Subject(s)
Neurons/drug effects , Receptors, Serotonin/drug effects , Adult , Aged , Binding Sites , Biphenyl Compounds/pharmacology , Cerebral Cortex/drug effects , Cerebral Cortex/metabolism , Female , Glutamic Acid/drug effects , Glutamic Acid/metabolism , Humans , Male , Middle Aged , Neurons/metabolism , Oxadiazoles/pharmacology , Piperazines/pharmacology , Piperidones/pharmacology , Potassium Chloride/pharmacology , Receptor, Serotonin, 5-HT1B , Receptor, Serotonin, 5-HT1D , Receptors, Serotonin/physiology , Serotonin/metabolism , Serotonin/pharmacology , Serotonin Antagonists/pharmacology , Spiro Compounds/pharmacology , Synaptosomes/drug effects , Synaptosomes/metabolism , Tritium
9.
J Neurosurg Sci ; 43(3): 205-8; discussion 208-9, 1999 Sep.
Article in English | MEDLINE | ID: mdl-10817389

ABSTRACT

Lymphocytic hypophysitis is a very unusual disease typically observed in the peripartum period but found also in non-pregnant women or in men. We report the case of a 50-year-old woman with a five-year history of erithema nodosus for which was treated with variable doses of steroids. One year before admission the patient began to complain of headache, amenorrhea and rapidly progressive hypopituitarism. Magnetic resonance imaging showed an expanding sellar mass with homogeneous contrast enhancement while lacking the hyperintense signal of posterior lobe. The MRI findings and the history of autoimmune disease raised the suspicion of hypophysitis. The growth of the lesion and its unresponsiveness to the prolonged steroid therapy made surgery, which is both diagnostic and therapeutic, mandatory. The pathogenesis, diagnosis and management of this unusual clinical condition are discussed.


Subject(s)
Erythema Nodosum/complications , Lymphocytes/pathology , Pituitary Diseases/etiology , Pituitary Diseases/pathology , Pituitary Gland/pathology , Erythema Nodosum/pathology , Female , Humans , Magnetic Resonance Imaging , Middle Aged , Pituitary Diseases/physiopathology
11.
Neurosurg Rev ; 19(1): 39-42, 1996.
Article in English | MEDLINE | ID: mdl-8738364

ABSTRACT

A case of cervical juxtamedullary meningeal melanocytoma is presented along with results of careful neuroradiological and pathological examinations. The authors review the previous literature and discuss the problems related to the intriguing diagnosis of this very rare entity. CT and MRI show variable appearances due to different degrees of melanization and do not reliably allow us to distinguish meningeal melanocytomas from other pigmented tumors. Pathological examination of the tumor is critical for diagnosis, but it absolutely must comprise electron microscopy and immunohistochemistry. Immunohistochemical and ultrastructural criteria are thus proposed to distinguish meningeal melanocytoma from pigmented meningioma or schwannoma and malignant melanoma (primary or secondary).


Subject(s)
Meningeal Neoplasms/diagnosis , Nevus, Pigmented/diagnosis , Spinal Cord Neoplasms/diagnosis , Biomarkers, Tumor/analysis , Diagnosis, Differential , Dura Mater/pathology , Dura Mater/surgery , Humans , Laminectomy , Magnetic Resonance Imaging , Male , Melanocytes/pathology , Meningeal Neoplasms/pathology , Meningeal Neoplasms/surgery , Microscopy, Electron , Middle Aged , Neurologic Examination , Nevus, Pigmented/pathology , Nevus, Pigmented/surgery , Spinal Cord Neoplasms/pathology , Spinal Cord Neoplasms/surgery , Tomography, X-Ray Computed
12.
Surg Neurol ; 43(5): 466-9; discussion 469-70, 1995 May.
Article in English | MEDLINE | ID: mdl-7660285

ABSTRACT

The authors report two cases of spinal dermoid cysts whose rupture originated the migration of free fat drops into the ventricles and intracranial subarachnoid spaces. In both cases the fat drops caused obstructive hydrocephalus, which represents a quite exceptional complication. Moreover, one of the cases is unique, since the finding of intracranial fat causing hydrocephalus considerably preceded the discovery of the spinal neoplasm. The authors suggest that the finding of intracranial fat in the absence of a local source makes the search for a intraspinal dermoid or epidermoid tumor mandatory.


Subject(s)
Dermoid Cyst/diagnosis , Hydrocephalus/etiology , Lipids , Spinal Cord Neoplasms/diagnosis , Cerebral Ventricles , Dermoid Cyst/complications , Diagnosis, Differential , Humans , Magnetic Resonance Imaging , Male , Middle Aged , Rupture, Spontaneous/complications , Rupture, Spontaneous/diagnosis , Spinal Cord Neoplasms/complications , Subarachnoid Space
13.
Neurosurgery ; 35(6): 1135-7, 1994 Dec.
Article in English | MEDLINE | ID: mdl-7885560

ABSTRACT

A case of cerebellopontine angle petrous bone osteoma manifesting as homolateral trigeminal neuralgia and causing a mild brain stem compression is presented. The literature concerning osteomas and particularly those affecting the temporal bone is reviewed. This is the second report of an osteoma located on the inner surface of the petrous bone and causing intracranial complications. Moreover, we discuss the intracranial tumors presenting with trigeminal neuralgia or atypical facial pain.


Subject(s)
Osteoma/complications , Petrous Bone , Skull Neoplasms/complications , Trigeminal Neuralgia/etiology , Brain Stem/pathology , Cerebellopontine Angle , Craniotomy/methods , Humans , Magnetic Resonance Imaging , Male , Middle Aged , Neurologic Examination , Osteoma/pathology , Osteoma/surgery , Petrous Bone/pathology , Petrous Bone/surgery , Skull Neoplasms/pathology , Skull Neoplasms/surgery , Tomography, X-Ray Computed , Trigeminal Neuralgia/pathology , Trigeminal Neuralgia/surgery
14.
J Neurochem ; 63(3): 1163-6, 1994 Sep.
Article in English | MEDLINE | ID: mdl-8051559

ABSTRACT

Fenfluramine is the most widely used anorexigenic drug in humans. In animal experiments d-fenfluramine has been shown to act as a potent releaser of brain serotonin [5-hydroxytryptamine (5-HT)]. Here we have investigated the effects of d-fenfluramine on the release of [3H]5-HT from isolated nerve endings of human neocortex. The drug elicited release of unmetabolized [3H]5-HT, and this effect was concentration dependent. However, the mechanism of release seems to differ profoundly depending on the concentrations of d-fenfluramine used. At 5 microM, the release of [3H]5-HT was blocked by the 5-HT transporter inhibitor fluoxetine and was Ca2+ independent and insensitive to the human autoreceptor 5-HT1D agonist sumatriptan. The release of [3H]5-HT elicited by 0.5 microM d-fenfluramine was similarly blocked by fluoxetine, but it was strongly Ca2+ dependent and sensitive to sumatriptan. It is suggested that, at relatively high concentrations, d-fenfluramine largely diffuses into serotonergic terminals and causes release of 5-HT through the 5-HT carrier working in the inside-outside direction; at relatively low concentrations d-fenfluramine enters the terminals through the 5-HT transporter but elicits release of 5-HT by an exocytotic-like mechanism.


Subject(s)
Cerebral Cortex/metabolism , Fenfluramine/pharmacology , Nerve Endings/metabolism , Serotonin/metabolism , Calcium/pharmacology , Cerebral Cortex/drug effects , Fluoxetine/pharmacology , Humans , Nerve Endings/drug effects , Sumatriptan/pharmacology , Synaptosomes/metabolism , Tritium
15.
J Neurosurg Sci ; 38(3): 167-70, 1994 Sep.
Article in English | MEDLINE | ID: mdl-7782862

ABSTRACT

The authors report a case of tension intraventricular pneumocephalus developed six months after the removal of an acoustic neuroma and a CSF ventriculoperitoneal shunt procedure due to a concomitant hydrocephalus. A review of the literature show only 19 cases of CSF shunt complicating pneumocephalus. The authors discuss both about the etiology of pneumocephalus and its therapeutic options. In our case we were unable to preoperatively localize the cranial base communication allowing intracranial air antry. The literature show however that eroded or thinned bone areas may be multiple and even diffuse their development depending upon several factors. We suggest in these cases a direct surgical repair through a craniotomy, as reported by others, is not mandatory. According to the etiology of pneumocephalus a temporary extraventricular drainage and the revision of the shunting pressure regimen may represent an effective treatment of this complication.


Subject(s)
Cerebrospinal Fluid Shunts , Pneumocephalus/etiology , Postoperative Complications/etiology , Female , Follow-Up Studies , Frontal Lobe/diagnostic imaging , Humans , Hydrocephalus/surgery , Incidence , Magnetic Resonance Imaging , Middle Aged , Neuroma, Acoustic/surgery , Pneumocephalus/diagnostic imaging , Pneumocephalus/surgery , Postoperative Complications/diagnostic imaging , Postoperative Complications/surgery , Reoperation , Temporal Lobe/diagnostic imaging , Tomography, X-Ray Computed
16.
Neurosurg Rev ; 17(1): 83-7, 1994.
Article in English | MEDLINE | ID: mdl-8078614

ABSTRACT

The authors report two cases of surgically treated brain metastases from endometrial cancer which are quite unusual occurrences. In one of them the brain lesion was the presenting symptom of malignancy while in the other the metastasis was discovered after the primary tumor had been treated. Both the brain lesions were scarcely differentiated adenocarcinomas which closely resembled the uterine primaries histologically. The authors review the four cases reported in the literature and discuss the clinical features and the treatment of this disease. The analysis of cases shows that the metastatic potential of endometrial cancer is extremely variable and unpredictable but less severe than that observed in ovarian or cervical tumors. The authors suggest that the erratic behaviour of endometrial cancer may justify an aggressive (though necessarily palliative) approach to brain metastases even in the presence of circumscribed metastatic involvement.


Subject(s)
Adenocarcinoma, Papillary/secondary , Brain Neoplasms/secondary , Endometrial Neoplasms/pathology , Adenocarcinoma, Papillary/diagnosis , Adenocarcinoma, Papillary/surgery , Brain Neoplasms/diagnosis , Brain Neoplasms/surgery , Female , Humans , Magnetic Resonance Imaging , Middle Aged , Tomography, X-Ray Computed
17.
Br J Pharmacol ; 110(1): 20-2, 1993 Sep.
Article in English | MEDLINE | ID: mdl-8106101

ABSTRACT

Slices from fresh specimens of human neocortex which had to be removed during neurosurgery to reach subcortical tumours were labelled with [3H]-dopamine and stimulated electrically. Quinpirole, a selective dopamine D2 receptor agonist, inhibited the stimulated tritium overflow (EC50 = 25 nM; maximal inhibition: about 80% at 10 microM). The selective D1 receptor agonist, SKF 38393, was inactive up to 10 microM. Quinpirole was antagonized by the D2 receptor antagonist (-)-sulpiride (apparent pA2 = 8.26). Thus dopaminergic axon terminals in the human mesocortical pathway possess autoreceptors of the D2 type.


Subject(s)
Cerebral Cortex/metabolism , Receptors, Dopamine/metabolism , 2,3,4,5-Tetrahydro-7,8-dihydroxy-1-phenyl-1H-3-benzazepine/pharmacology , Adult , Cerebral Cortex/physiology , Dopamine/metabolism , Dopamine Agents/pharmacology , Electric Stimulation , Ergolines/pharmacology , Female , Humans , In Vitro Techniques , Male , Middle Aged , Quinpirole , Receptors, Dopamine/drug effects , Receptors, Dopamine D1/drug effects , Receptors, Dopamine D1/metabolism , Receptors, Dopamine D2/drug effects , Receptors, Dopamine D2/metabolism , Sulpiride/pharmacology
18.
J Neurochem ; 60(3): 1179-82, 1993 Mar.
Article in English | MEDLINE | ID: mdl-8382263

ABSTRACT

Release-regulating 5-hydroxytryptamine (5-HT) autoreceptors in the rat brain belong to the 5-HT1B subtype. On the other hand, the human brain seems to lack 5-HT1B receptors. In the present work 5-HT autoreceptors present in human brain were characterized pharmacologically. Synaptosomes prepared from biopsy samples of human neocortex were labeled with [3H]5-HT and exposed in superfusion to selective 5-HT receptor agonists and antagonists during K+ depolarization. The rank order of potency of agonists as inhibitors of the [3H]5-HT overflow was 5-HT > sumatriptan (5-HT1D/1B) > 8-hydroxy-2-(di-n-propylamino)tetralin (5-HT1A/1D) >> 1-(2,5-dimethoxy-4-iodophenyl)-2-aminopropane HCl (5-HT2/1C). The effect of 5-HT was insensitive to ketanserin (5-HT2) but antagonized by methiothepin (5-HT1/2) or by metergoline (5-HT1C/1D). The data are compatible with a classification of the human 5-HT autoreceptor as being of the 5-HT1D subtype.


Subject(s)
Cerebral Cortex/metabolism , Receptors, Serotonin/metabolism , Synaptosomes/metabolism , 8-Hydroxy-2-(di-n-propylamino)tetralin/pharmacology , Adult , Aged , Female , Humans , Indoles/pharmacology , Male , Middle Aged , Potassium/pharmacology , Serotonin Antagonists , Serotonin Receptor Agonists/pharmacology , Sulfonamides/pharmacology , Sumatriptan
19.
Br J Pharmacol ; 107(4): 1146-51, 1992 Dec.
Article in English | MEDLINE | ID: mdl-1361400

ABSTRACT

1. Release-regulating alpha 2-autoreceptors in human brain were characterized pharmacologically in cortical slices from patients undergoing neurosurgery to remove subcortical tumours; the slices were prelabelled with [3H]-noradrenaline ([3H]-NA) and stimulated electrically (3 Hz, 2 ms, 24 mA) under superfusion conditions. 2. The stimulus-evoked tritium overflow was almost totally Ca(2+)-dependent and tetrodotoxin-sensitive. 3. Clonidine and oxymetazoline 0.01 to 1 microM inhibited in a concentration-dependent manner the evoked overflow of tritium. The two drugs were equipotent (EC50 = 0.03 microM) and their maximal effect was approx. 45%. Phenylephrine and methoxamine, up to 1 microM, did not affect tritium overflow. 4. Yohimbine (0.01-0.1 microM) shifted the concentration-response curve of clonidine to the right. The calculated pA2 value was 8.29. 5. Prazosin and 2-[2-[4-(o-methoxyphenyl)piperazine-1-yl]ethyl]-4,4- dimethyl-1,3(2H,4H)-isoquinolinedione (AR-C 239), tested at 0.3 microM, did not modify the concentration-response curve of clonidine. 6. The effect of clonidine was antagonized by (+)-mianserin (pA2 = 7.74), but not by up to 0.3 microM of the (-)-enantiomer. The concentration-response curve of clonidine was shifted to the right by the novel alpha 2-adrenoceptor antagonist, 5-chloro-4-(1-butyl-1,2,5,6-tetrahydropyridin-3-yl)-thiazole-2-ami ne (Z)-2-butenedioate (1:1) salt (ORG 20350) (pA2 = 7.55). 7. Yohimbine, (+)-mianserin and ORG 20350, but not prazosin and (-)-mianserin, increased the electrically-evoked tritium overflow, suggesting that autoreceptors may be tonically activated by endogenous NA. 8. Desipramine (1 microM) increased evoked tritium overflow from human cortex slices. The effect of clonidine (0.01- 1 g1M) on the evoked overflow of tritium was reduced in presence of 1 muM desipramine.9. It is proposed that autoregulation of NA release can occur in human cerebral cortex. The process involves activation of alpha 2-adrenoceptors which may be either the alpha2X or the alpha2D subtype.


Subject(s)
Adrenergic alpha-Agonists/pharmacology , Adrenergic alpha-Antagonists/pharmacology , Cerebral Cortex/metabolism , Norepinephrine/metabolism , Receptors, Adrenergic, alpha/classification , Adult , Aged , Calcium/metabolism , Cerebral Cortex/drug effects , Clonidine/pharmacology , Desipramine/pharmacology , Dose-Response Relationship, Drug , Electric Stimulation , Female , Humans , In Vitro Techniques , Male , Middle Aged , Oxymetazoline/pharmacology , Receptors, Adrenergic, alpha/metabolism , Tetrodotoxin/pharmacology
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