Detection of vasopressin mRNA in cells of the medial amygdala but not the locus coeruleus by in situ hybridization.

Vasopressin (AVP)-immunoreactive cells have been previously reported in the medial amygdala (AME) and in the locus coeruleus (LC). The present study was designed to verify the presence of AVP-synthesizing neurons in these areas using in situ hybridization histochemistry. A 35S-labelled oligonucleotide probe, complementary to the glycopeptide portion of the vasopressin-encoding mRNA, was used to label cells expressing the AVP gene in brain sections from male Wistar rats. AVP mRNA-positive cells were identified in the AME and were located throughout the anterodorsal and posterodorsal aspect of the nucleus. Cells in the LC, however, did not exhibit labelling for the glycopeptide portion of the AVP gene. The highest density of labelled cells in the medial amygdala occurred 2.30 to 2.80 mm caudal to bregma. The labelling intensity of the cells averaged 53.8 +/- 3.9 grains/cells and was constant throughout the rostro-caudal extent of the AME. These data demonstrate the presence of AVP-synthesizing cells in the AME and provide a method for quantifying their activity. In addition, these data suggest that the cells in the LC may not synthesize vasopressin.

Distribution of neuropeptide Y in the prosencephalon of man and cotton-head tamarin (Saguinus oedipus): colocalization with somatostatin in neurons of striatum and amygdala.

The presence, chromatographic properties and localization of neuropeptide Y was demonstrated in postmortem human brain areas of neurologically and neuropsychiatrically normative controls using immunocytochemistry and high performance liquid chromatography combined with radioimmunoassay. NPY-immunoreactivity was found in many regions of the prosencephalon. Numerous perikarya and fibers were present in the neocortex, basal ganglia and limbic-hypothalamic areas. A moderate number of neurons and fibers was observed in the basal forebrain, including the septal complex. A comparative immunohistochemical investigation in perfusion-fixed brains of the old-world ape Saguinus oedipus revealed an almost identical distribution of NPY-immunoreactivity with only minor differences. Colocalization experiments on 1-2 microns thin consecutive paraffin sections revealed a large number of NPY neurons throughout the human neostriatum and amygdaloid complex that were also positive for somatostatin. Our findings indicate that detection of neuropeptides in fresh or fixed post-mortem human tissue by different immunochemical methods may actually reflect the in vivo conditions. In addition, the wide distribution of NPY throughout the human brain and its colocalization with other neurotransmitters suggests a physiological role as neuroactive substance, i.e. neuromodulator in the primate central nervous system.

[Role of serotonin receptors in the amygdaloid complex and central gray substance in conditioned passive avoidance reaction in rats]. / Uchastie serotoninovykh retseptorov mindalevidnogo kompleksa i tsentral'nogo serogo veshchestva v vosproizvedenii uslovnoi reaktsii passivnogo izbeganiia u krys.

The functional role of 5-HT1 receptors in the memory trace retrieval was investigated in amygdala (AM), central gray substance of midbrain (CGS) and frontal cortex. There is used the passive avoidance response in the rat. The decrease of 5-HT1 binding sites in AM and CGS was revealed for the rats with retention of the passive avoidance response. The binding of 3H-5-HT in AM was found two sets of binding sites. It was concluded, that 5-HT1 receptors of AM and CGS are involved in learning processes either in the moment of the memory trace retrieval or immediately after it.

The effect of repeated administration of antidepressant drugs on the thyrotropin-releasing hormone (TRH) content of rat brain structures.

The present study investigated the effect of repeated treatment with the antidepressant drugs imipramine, amitryptyline, citalopram and mianserin (10 mg/kg PO, twice daily for 14 days) on levels of thyrotropin-releasing hormone (TRH) in several brain structures (cerebral cortex, amygdala + pyriform cortex, hippocampus, nucleus accumbens, striatum and hypothalamus) of the rat. Amitriptyline caused a marked increase in the TRH content in the striatum and nucleus accumbens. Citalopram and mianserin produced a smaller but significant increase in the TRH content in the striatum only, while imipramine did not significantly affect the TRH concentrations in any of the brain structures. None of the antidepressant drugs administered acutely significantly affected the TRH concentrations in the nucleus accumbens or the striatum. These results indicate that changes in brain TRH induced by antidepressant drugs are not related to their therapeutic activity.

[A study on PP family peptide receptor: I. The distribution of peptide YY (PYY) receptor in the brain].

Peptide YY (PYY) was discovered in the porcine gut by Tatemoto in 1982. PYY has recently been found in the central nervous system. This has provoked studies of PYY effects when centrally administrated. We investigated the specific binding of radioactive PYY (125I-PYY) to brain membranes in pigs and dogs. PYY chiefly bound to the hippocampus, as well as to the pituitary gland, hypothalamus, and amygdala, suggesting that PYY acts on the limbic-hypothalamic-pituitary axis. PYY binding in the brain had a high-affinity and a low-affinity component (dissociation constant, 1.39 X 10(-10) M and 3.72 X 10(-8) M, respectively). The binding sites were highly specific for PYY and neuropeptide Y (NPY), but not for pancreatic polypeptide (PP) or other peptide hormones such as cholecystokinin octapeptide, methionine enkephalin, adrenocorticotropic hormone, and thyrotropic releasing hormone. The similar affinities for PYY and NPY imply that these peptides regulate brain functions through interaction with common receptor site(s).

Atrial natriuretic factor content of brain nuclei in deoxycorticosterone acetate-salt hypertension in the rat.

1. The influence of deoxycorticosterone acetate (DOCA)-salt hypertension on brain atrial natriuretic factor (ANF) in rats was investigated to elucidate the role of central ANF in a renin-independent model of experimental hypertension. 2. Sprague-Dawley rats were subjected to uninephrectomy and given either tap water or saline [1% (w/v) NaCl] to drink plus weekly injections of either saline or DOCA (25 mg/kg, subcutaneously). After 32 days, the rats were decapitated and 18 different brain nuclei were removed by a micropunch technique. 3. The systolic blood pressure of the DOCA-salt rats was significantly higher than that of control rats [154 +/- 3 mmHg vs 104 +/- 2 mmHg (20.53 +/- 0.40 kPa vs 13.86 +/- 0.27 kPa), P less than 0.001]. 4. Plasma ANF levels were significantly (P less than 0.01) higher in DOCA-salt hypertensive rats compared with control rats. 5. In DOCA-salt hypertensive rats, the ANF content was increased in the organum vasculosum of the lamina terminalis (31.4 +/- 2.1 vs 22.1 +/- 2.5 pg/mg of protein, P less than 0.05), the subfornical organ (32.5 +/- 5.0 vs 24.2 +/- 2.4 pg/mg of protein, P less than 0.05), the medial amygdaloid nucleus (49.0 +/- 6.4 vs 34.0 +/- 2.0 pg/mg of protein, P less than 0.05) and the locus coeruleus (86.9 +/- 4.1 vs 64.4 +/- 4.2 pg/mg of protein, P less than 0.01) compared with control rats. The ANF content of 14 other brain areas investigated did not alter after treatment.(ABSTRACT TRUNCATED AT 250 WORDS)

Critical exposure time for androgen activation of male sexual behavior in rats.

We determined the minimum number of hours per day of testosterone (T) exposure required to activate male sexual behavior, and correlated these changes with the temporal parameters of androgen receptor occupation. For the first part of the study, castrated Long-Evans male rats received two 10 mm T-filled Silastic capsules in open flank pouches for 4, 8, 12, 16, 18, 21, or 24 hours per day over a 10 day period. Tests for male sexual behavior were conducted on days 2-3, 4-5, 7-8, and 9-10 of T treatment. A significantly higher proportion of males receiving 21 or 24 hr of daily T exposure mounted, intromitted and ejaculated compared to groups with daily T exposures of 18 hr or less. In the second part of this study we assessed whether it was necessary to maintain high levels of androgen receptor occupation during the 21-24 hr exposure period in order to activate male sexual behavior. Cell nuclear androgen receptor occupation was measured in HPAS (combined hypothalamus, preoptic area, amygdala and septum) of rats receiving 12, 21, or 24 hr of T exposure. In all three groups, nuclear androgen receptor occupation was high at the time of capsule removal, and fell significantly by 3 hr following T capsule removal. By 6 hr after T capsule removal, androgen receptor binding had fallen to castrate levels. These results demonstrate that, although relatively brief (less than or equal to 18 hr/day) exposures to testosterone can activate mounts and intromissions, significantly more responses are found in males receiving at least 21 hr of T exposure per day.(ABSTRACT TRUNCATED AT 250 WORDS)

[Contents of serotonin and 5-hydroxyindoleacetic acid in the rabbit brain after long-term administration of lithium oxybutyrate]. / Soderzhanie serotonina i 5-oksiindoluksusnoi kisloty v mozge krolikovpri dlitel'nom naznachenii oksibutirata litiia.

Serotonin (5-HT) and 5-hydroxyindoleacetic acid (5-HIAA) levels in rat brain were analysed 24 hours after 7-, 15-, 29- days lithium hydroxybutyrate (LH) injections (10 mg/kg daily). After 7 days the drug reduced 5-HT in hypothalamus and 5-HIAA in the mid brain by 35%. After 15 days LH decreased 5-HT in striatum, hypothalamus by 32 and 17% and 5-HIAA in thalamus, hypothalamus by 28 and 44% respectively. After 29 days LH diminished 5-HT in striatum, hippocampus, amygdala by 24, 29 and 32% and 5-HIAA--in hypothalamus by 42%. The role of adaptative changes and stabilization processes in the central serotoninergic system in mechanism of LH psychotropic effects is discussed.

[5-HT1 receptors in rats with amnesia]. / Serotoninovye retseptory pervogo tipa pri amnezii u krys.

5-HT1 receptors of the amygdala, midbrain's central gray substance, hippocampus and frontal cortex of the rats were investigated during the memory trace retrieval, using the model of "psychogenic" amnesia. It was found that specific binding of 3H 5-HT in amygdala and central gray substance was decreased in the rats with passive avoidance retention. 3H 5-HT binding in the amnesic rats didn't differ from the control animals. Absence of decrease of 5-HT1 receptors number could be considered as one of the possible mechanisms of the memory trace non-retrieval due to amnesia or its consequence.

Morphology of peptide-immunoreactive neurons in the rat central nucleus of the amygdala.

The morphological characteristics of peptide-immunoreactive neurons in the rat central nucleus of the amygdala were examined. Observations were compared with details of neuron morphology available from Golgi-stained tissue to determine whether peptide immunoreactivity was associated with specific cell types in the central nucleus. The lateral subdivision (CL) of the central nucleus contained mainly medium-sized, densely spiny neurons. Larger, pyramiform spiny neurons; medium-sized, sparsely spinous neurons; and small, aspinous cells were also present in CL. Somatostatin-, neurotensin-, corticotropin-releasing factor (CRF)-, and enkephalin-immunoreactive neurons in CL were characterized as the medium spiny and larger, pyramiform types. No obvious morphological differences were evident among medium spiny neurons containing different peptides. In the medial subdivision, substance P, neurotensin, somatostatin, and CRF were present within pyramiform, sparsely spinous neurons with long dendrites. Galanin immunoreactivity in the medial subdivision was associated with moderately spiny, pyramiform neurons and a larger, aspinous, polygonal neuron. The ventral subdivision of the central nucleus contained neurons similar to those found in the adjacent medial and lateral subdivisions. In addition, this subdivision contained a characteristic ovoid neuron with long, sparsely spinous dendrites. Vasoactive intestinal polypeptide (VIP) and neurotensin appeared to be present within this cell type. In the lateral capsular subdivision, neurotensin and enkephalin were present in cells resembling the medium spiny neurons characteristic of this part of the central nucleus. Numbers of spindle-shaped, biopolar somatostatin, and VIP neurons were identified in the medial, lateral, and ventral subdivisions. The present results provide evidence for a heterogeneous morphology of peptide-immunoreactive neurons in the rat central nucleus that are distributed across cytoarchitectonic boundaries. Except for substance P, neuropeptides in the central nucleus appear to be expressed by a variety of neurons rather than morphologically characteristic types of cell.

[Catecholaminergic systems in the amygdaloid complex of SDAT and aged controls: tyrosine hydroxylase immunohistochemistry].

Catecholaminergic systems in the amygdaloid complex in patients with senile dementia of Alzheimer type (SDAT) and aged controls have been studied with tyrosine hydroxylase (TH) immunohistochemistry. TH-immunoreactivity was found in fibers in all subnuclei of human amygdala, although varying in density in the subnuclei. The most dense catecholaminergic innervation was observed in the central, basal, and cortical nuclei of amygdala. The prominent finding in the amygdaloid complex of SDAT was that swollen and bulbous TH-immunoreactive neurites were found in association with neuritic plaques, which have not, rarely if any, been found in controls. The numerical density of neurites was mostly in parallel with that of TH-immunoreactive fibers except for the central nucleus. Thus, it is suggested that a class of populations of TH-immunoreactive neurons are selectively affected in the amygdaloid complex in SDAT.

Regional variation in rat brain proton relaxation times and water content.

Relaxation times (T1 and T2) and water content are measured in frontal cortex, amygdaloid cortex, hippocampus, mid-brain and cerebellum of rat brain. Differences are found in relaxation times, between areas containing a mixture of grey and white matter, and grey matter only. Differences were also found between certain grey matter areas. Relaxation times correlated with water content.

Autoradiographic analysis of tritiated imipramine binding in the human brain post mortem: effects of suicide.

In vitro quantitative autoradiography of high-affinity tritiated imipramine binding sites was performed on brains of 12 suicide victims and 12 matched controls. Region-specific differences in imipramine binding were found between the two groups. Thus, the pyramidal and molecular layers of the cornu ammoni hippocampal fields and the hilus of the dentate gyrus exhibited 80%, 60%, and 90% increases in binding in the suicide group, respectively. The postcentral cortical gyrus, insular cortex, and claustrum had 45%, 28%, and 75% decreases in binding in the suicide group, respectively. No difference in imipramine binding was observed in prefrontal cortical regions, in the basal ganglia, and in mesencephalic nuclei. No sex and postmortem delay effects on imipramine binding were found. Imipramine binding was positively correlated with age, the effect of age being most pronounced in portions of the basal ganglia and temporal cortex.

[Prolactin-secreting neurons in the dorsolateral hypothalamus in Sprague-Dawley rats]. / Neurones à prolactine dans l'hypothalamus dorso-latéral du rat Sprague-Dawley.

By means of immunocytochemical techniques ovine prolactin like immunoreactivity (oPRL-LIR) has been demonstrated in the perikarya located around fornix in the dorso-lateral part of the rat hypothalamus. No PRL-LIR was observed in the arcuate n. perikarya. Immunoreactive fibers were present in the hypothalamus, medial thalamus, accumbens and amygdaloid nuclei.

Neuropeptides and neuropathology in the amygdala in Alzheimer's disease: relationship between somatostatin, neuropeptide Y and subregional distribution of neuritic plaques.

This study examined the amygdaloid complex in Alzheimer's disease (AD). We compared the distribution and morphology of somatostatin (SOM-) and neuropeptide Y-immunoreactive (NPY-IR) neurons in the amygdala with the distribution of neuritic plaques (NP) and acetylcholinesterase (AChE) staining patterns in various subnuclei. We found that in AD, there was an increase in the number of small, atrophic neurons for both SOM and NPY, and subregional analysis revealed similar size reductions in all subnuclei. In contrast, the highest density of NP was found in the corticomedial nuclei and densest staining for AChE in the basal nucleus. Although NPY- and SOM-IR fibers were occasionally associated with NP, a dense, morphologically preserved peptidergic fiber-network was found in all areas including subnuclei with high numbers of NP. Our study indicates that atrophic SOM- and NPY-IR neurons are not correlated with the subregional distribution of NP or cholinesterase staining pattern of the amygdala, and suggests that alterations in SOM and NPY neurons are not characteristics of the primary pathogenic process that underlie the formation of NP or cholinergic cell loss in AD.

[Effect of amygdaloid kindling on thyrotropin-releasing hormone, somatostatin, cholecystokinin and substance P contents of the amygdala/piriform cortex and hippocampus of rats].

Recently, several systems of neuropeptides have been demonstrated to have anticonvulsant action in some forms of epilepsy to some extent. However, considerably less knowledge has been taken to their involvement in convulsive disorders either with regard to the development, expression or control of seizures. In this study, therefore, we examined the influence of amygdaloid kindling, an experimental model of temporal lobe epilepsy, on thyrotropin-releasing hormone (TRH), somatostatin (SS), cholecystokinin (CCK) and substance P (SP) content in the amygdala/piriform cortex and hippocampus. Male Sprague-Dawley rats were implanted bipolar electrodes into the left amygdala under pentobarbital anesthesia. Daily kindling stimulation was made to the left amygdala with 1 sec, 60 Hz, 400 microA, until 5 consecutive fully kindled generalized convulsive seizures were elicited. Subsequently, amygdaloid kindled rats were decapitated 30 min, 24 hrs, 48 hrs, 7 days and 21 days after the last amygdaloid stimulation, and the amygdala/piriform cortex and hippocampus were dissected. Control animals only received chronic electrodes, but no stimulation was delivered. The immunoreactivity of TRH, SS, CCK and SP was examined by methods of specific radioimmunoassay. The TRH content in these two brain regions significantly increased 24 hrs after the last kindled convulsion. This increase became maximal 48 hrs after the last convulsion: about 3-fold and 4-fold of the control in the amygdala/piriform cortex and hippocampus, respectively. Such increases in the TRH content tended to persist for 7 days, but returned to the control level 21 days after the last convulsion.(ABSTRACT TRUNCATED AT 250 WORDS)

Distribution of cholecystokinin-immunoreactive cell bodies in the male and female rat: II. Bed nucleus of the stria terminalis and amygdala.

The distribution of cholecystokinin-immunoreactive (CCK-I) cell bodies was studied in the bed nucleus of the stria terminalis (BST) and amygdaloid complex of colchicine-treated male and female rats. Immunoreactive cells were visualized in the BST medial amygdaloid (MeA), central lateral, basolateral, basolateral ventral, medial, intercalated, anterior cortical, and posterior cortical nuclei and the amygdalohippocampal zone. Several significant sex differences were observed. In the male, a dense aggregation of CCK-I cell bodies was visualized in the MeA, especially in the dorsocaudal part and in the encapsulated part of the BST. In comparison, female rats had relatively fewer immunoreactive cells in both of these regions. In the lateral and basolateral amygdaloid nuclei, however, more CCK-I cells were visualized in the female than in the male, but the difference was not statistically significant. These data provide characterization of a sexually differentiated CCK system. In addition, we observed that the number of CCK-I cells in the BST and posterodorsal part of the MeA was substantially reduced after castration. The number of CCK-I cells in female rats, however, was not significantly reduced after ovariectomy in any of the regions studied. These findings imply that the steroid regulation of CCK is sexually differentiated. The sexually dimorphic distribution of CCK-I cells in areas that are targets of steroid hormones and regulate reproductive processes is consistent with the possibility that CCK participates in central integration of sensory and steroidal input that modulates reproductive behavior.

Projection of neurotensin-like immunoreactive neurons from the lateral parabrachial area to the central amygdaloid nucleus of the rat with reference to the coexistence with calcitonin gene-related peptide.

The origin of neurotensin-like immunoreactive (NTI) fibers in the central amygdaloid nucleus (AC) in the rat was examined using indirect immunofluorescence and retrograde tracing combined with immunocytochemistry. Destruction of the external subdivision of the lateral parabrachial nucleus, which contains a group of NTI neurons, resulted in a marked reduction of these fibers in the ipsilateral AC, which suggests that most of these fibers are of extrinsic origin. This was also supported by the finding that injection of fast blue dye into the AC labeled many neurons in the external subdivision of the lateral parabrachial nucleus ipsilaterally, and that simultaneous treatment with antiserum against NT stained some of these neurons. Subsequent immunohistochemical staining of alternate sections revealed that many of these NTI neurons were also labeled by calcitonin gene-related peptide antiserum.