Single-site robotic cholecystectomy (SSRC): an initial review of safety and feasibility.

AIM: This report comprehensively reviews the findings from initial experiences with single-site robotic cholecystectomy (SSRC) across the world, and reports the feasibility of this new approach and novel platform. It attempts to be impartial in evaluating this novel robotic platform and approach. METHODS: A search utilizing MEDLINE®/PubMed® and Google Scholar was undertaken to identify articles about SSRC. Eleven articles met our criteria and were reviewed. Data collected included: patient demographic, preoperative, intraoperative, and postoperative data. Data are presented as weighted means±pooled standard deviations. RESULTS: Age and BMI was 46±13.1 years and 26±4.2 kg/m2, respectively. Operative time was 80±24.1 minutes; robotic console time was 38±16.9 minutes; and docking time was 7±3.1 minutes. Blood loss ranged from 0-150 mL. Ninety-eight percent of SSRC undertaken were completed robotically without the addition of other trocars/incisions, 2% of operations had additional trocars added, and three operations (<1%) were converted to "open". Postoperative hospital stay was 26 hours. Pain ratings, determined 2-3 weeks postoperatively, ranged from 0-2 on a Likert scale. CONCLUSION: This study serves as an overall analysis and review of SSRC. Existing reports of initial experiences with SSRC documents the operation is safe, feasible, and easily learned by surgeons from a broad spectrum of geographic areas. However, a detailed cost analysis is necessary in order to determine what the future holds for this novel approach.

Evolution of segmental anesthesia for Laparo-Endoscopic Single Site (LESS) cholecystectomy.

AIM: Transumbilical Laparo-Endoscopic Single Site (LESS) surgery promises improved cosmesis, quick recovery, reduced postoperative pain and shorter length of hospital stay. Since only a simple umbilical incision is used, LESS surgery can be completed with segmental epidural anesthesia. This study describes the evolution of our technique of LESS cholecystectomy from a combination of spinal and epidural anesthesia to thoracic epidural alone and presents our experience with its safety, the observed morbidity, and the reported patient satisfaction. METHODS: In August 2009, a prospective evaluation of LESS cholecystectomy with regional anesthesia was undertaken. We recruited patients with chronic cholecystitis or symptomatic cholelithasis. Blood loss, operative time, complications, and length of hospital stay were measured. Preoperatively and 14 days postoperatively, outcome and symptom resolution were scored. RESULTS: Fifteen consecutive patients underwent LESS cholecystectomy; first with combined spinal-epidural (CSE), and then with thoracic epidural anesthesia alone. Immediate postoperative pain and discomfort were well tolerated. VAS scores upon admission to PACU were 0.4 (1.7±2.2). At postoperative day 14, the patients scored high values for "Satisfaction", 10 (10±1.0) and "Cosmesis", 10 (9.3±1.5). CONCLUSION: LESS cholecystectomy with epidural anesthesia can be undertaken safely. Patient satisfaction and cosmesis are particularly prominent amongst our patients. Our experience supports further utilization of epidural anesthesia for selected patients undergoing LESS cholecystectomy.

Evidence for involvement of protein kinases in the regulation of serotonin synthesis and turnover in the mouse brain in vivo.

Inhibition of cAMP-dependent protein kinase (PKA) with N-[2-methylamino)ethyl]-5-isoquinolinesulfonamide (H-8) almost completely antagonized the increase in 5-HTP accumulation and 5-HIAA/5-HT ratio in hypothalamus induced by NAS-181, a 5-HT(1B) receptor antagonist, but had no effect when the mice were treated with NAS-181 together with WAY-100,635, a selective 5-HT(1A) receptor antagonist. Inhibition of Ca(2+)-calmodulin-dependent protein kinase (CaM kinase II) with the calmodulin antagonist N-(4-aminobutyl)-5-chloro-2-naphtalenesulfonamide (W-13) did not antagonise the effect of NAS-181 alone, but counteracted that evoked by the combined treatment with NAS-181 and WAY-100,635. The results indicate that activation of tryptophan hydroxylase by reducing the tone from terminal 5-HT(1B) receptors involves PKA whereas the depolarisation-induced activation of tryptophan hydroxylase involves CaM kinase II. The increase in the 5-HIAA/5-HT ratio may under the experimental conditions used suggest CaM kinase II-induced phosphorylation of synapsin I resulting in increased 5-HT release.

The pharmacological profile of (R)-3,4-dihydro-N-isopropyl-3-(N-isopropyl-N-propylamino)-2H-1-benzopyran-5-carboxamide, a selective 5-hydroxytryptamine(1A) receptor agonist.

The pharmacological properties of the 5-hydroxytryptamine (HT)(1A) receptor agonist (R)-3,4-dihydro-N-isopropyl-3-(N-isopropyl-N-propylamino)-2H-1-benzopyran-5-carboxamide (NAE-086) were examined with in vitro and in vivo techniques. Receptor binding studies demonstrated that NAE-086 was a high-affinity and selective 5-HT(1A) receptor ligand with a K(i) value of 4.5 nM in membranes from rat hippocampus. Of 32 other receptors examined NAE-086 had a modest affinity only for the 5-HT(7) receptor (K(i) = 240 nM). NAE-086 inhibited VIP-stimulated adenylyl cyclase activity in GH(4)ZD10 cells with 79% of the efficacy of 5-HT. This inhibition was blocked by the 5-HT(1A) receptor (and beta-adrenoceptor) antagonist (-)alprenolol. A minor metabolite of NAE-086 in rats, (R)-3,4-dihydro-3-(N-isopropyl-N-propylamino)-2H-1-benzopyran-5-carboxamide had a similar receptor profile but had 17 times higher affinity for the 5-HT(1A) receptor (K(i) = 0.26 nM). In vivo, NAE-086 induced all the typical effects of a 5-HT(1A) receptor agonist in rats: it decreased 5-HT synthesis (5-HTP accumulation) and 5-HT turnover (measured as the ratio of 5-hydroxyindoleacetic acid/5-HT), increased corticosterone secretion, induced the 5-HT(1A) syndrome (flat body posture and forepaw treading), inhibited the cage-leaving response, and caused hypothermia. All the responses mediated by postsynaptic 5-HT(1A) receptors were attenuated after single or repeated treatment of the rats with NAE-086. Simultaneously with the development of the tolerance to 5-HT(1A) receptor-mediated responses, 5-HT(2A) receptor-mediated responses were enhanced, as judged from the increased number of spontaneous and/or agonist [1-(2,5-dimethoxy-4-iodophenyl)-2-aminopropane]-induced wet-dog shake responses. The significance of this behavioral effect in relation to clinical observations is discussed.

Hypothermia reduces the rate of dissociation of specific ligands from dopamine-D2 and 5-hydroxytryptamine1A receptors in the mouse brain in vivo.

Factors influencing the disappearance of radioactivity from mouse brain after injections of tracer doses of the very selective receptor antagonists [3H]raclopride and [3H]robalzotan (NAD-299) which bind with high affinity to dopamine-D2 and 5-hydroxytryptamine1A receptors, respectively, were studied. For both ligands the amount of radioactivity in cerebellum was taken as non-specific binding and subtracted from the amount of radioactivity found in the brain regions studied. The disappearance of the radioactivity in naive mice followed apparent first-order reactions with T1/2=16.8+/-1.4 min for [3H]raclopride in striatum and T1/2=22+/-2 min and 17+/-2 min for [3H]robalzotan in hippocampus and frontal cortex, respectively. Pretreatment of mice with 1 mg/kg s.c. reserpine 20 h before the experiment strongly prolonged the dissociation phase for the two ligands. Injection of the dopamine-D2 receptor antagonist etioclopride 1 h after [3H]raclopride in the reserpinized mice rapidly reduced the radioactivity in striatum to the same level as in cerebellum. Similarly, the 5-HT1A receptor antagonist WAY-100,635 injected 1 h or 4 h after [3H]robalzotan rapidly reduced the radioactivity in hippocampus and frontal cortex to the cerebellum level showing that the intact drugs were still bound to the receptors. In reserpinized mice kept at 30 degrees C 1 h before and during the experiment, which normalised the body temperature, the disappearance of radioactivity was more like that in untreated animals but was still significantly higher than in the control animals. Mice treated with anaesthetic agents, e.g. gamma-butyrolactone (GBL), pentobarbital sodium and chloral hydrate, also strongly prolonged the rate of disappearance of [3H]raclopride and [3H]robalzotan from the receptor-rich brain regions. The pronounced effect of hypothermia on the dissociation of these 3H ligands from their receptors is probably caused by a general decrease in brain nervous activity. However, the decreased rate of dissociation evoked by reserpine, GBL, baclofen and prazosin after normalisation of the body temperature may be due to specific actions of these compounds causing decrease in dopaminergic and serotoninergic nerve activity which results in reduced synaptic concentration of the transmitter amines. In accordance with this view, increased synaptic 5-HT evoked by the 5-HT releasing agent p-chloroamphetamine enhanced the disappearance of [3H]robalzotan from hippocampus and frontal cortex.

Pharmacological characterisation of the decrease in 5-HT synthesis in the mouse brain evoked by the selective serotonin re-uptake inhibitor citalopram.

The selective serotonin re-uptake inhibitor (SSRI) citalopram decreases the synthesis of 5-hydroxytryptamine (5-HT) in the mouse brain in vivo. The underlying mechanism was studied by recording the accumulation of 5-hydroxytryptophan (5-HTP) in hypothalamus and hippocampus after inhibition of the aromatic amino acid decarboxylase activity with m-hydroxybenzylhydrazine (NSD 1015). Depletion of 5-HT with reserpine markedly reduced the citalopram-induced decrease of 5-HTP but not that evoked by the 5-HT1A receptor agonist 8-OH-DPAT, which indicates that the presence of endogenous 5-HT is necessary for full effect of citalopram. In contrast to the almost complete antagonism of the decrease in 5-HT synthesis induced by 8-OH-DPAT, the 5-HT1A receptor antagonist WAY-100,635 only slightly affected the citalopram-evoked decrease in 5-HT synthesis. Likewise, the 5-HT1B receptor antagonists NAS-181 and GR127935 only slightly antagonised the citalopram effect although they strongly inhibited the decrease in 5-HT synthesis induced by the 5-HT1B receptor agonist anpirtoline. Combined treatment with 5-HT1A and 5-HT1B receptor antagonists did not produce any additive antagonistic effect on the citalopram-induced decrease in 5-HT synthesis. The 5-HT2A/2C receptor antagonist ketanserin, the 5-HT3 receptor antagonist ondansetron and the 5-HT4 receptor antagonist RS-39604 had no effect on the citalopram-induced decrease in 5-HT synthesis. The same was found for several other non-selective 5-HT receptor antagonists, e.g. cyproheptadine, dihydroergotamine, methiothepin, methysergide, metergoline and mianserin. It is concluded that the citalopram-induced decrease in 5-HT synthesis differs in sensitivity from that mediated by 5-HT1A or 5-HT1B receptor agonists and citalopram also seems to require endogenous 5-HT for its full effect.

Differential sensitivity to 8-hydroxy-2-(di-n-propylamino)tetralin-induced corticosterone secretion and hypothermia between Sprague-Dawley rats from different breeding colonies.

The sensitivity of Sprague-Dawley rats from 4 different breeding colonies (ALAB, M&B, B&K, Charles River) and one breeding colony of Wistar rat (M&B) to the 5-hydroxytryptamine1A (5-HT1A) receptor stimulatory effect of 8-hydroxy-2-(di-n-propylamino)tetralin hydrobromide (8-OH-DPAT) resulting in corticosterone secretion and hypothermia was compared. The dose-response curves of the increase in plasma corticosterone showed that ALAB and M&B rats were 3.5 times more sensitive to 8-OH-DPAT than B&K and Charles River rats, the Wistar rats being in between. The attenuation of the corticosterone response 24 hr after a single injection of 1 mg/kg 8-OH-DPAT was greater for the ALAB and M&B rats than for B&K, Charles River and Wistar rats. The comparison of the 8-OH-DPAT-induced hypothermia in the various rat colonies showed a similar pattern: the sensitivity of ALAB rats was about twice that of M&B, B&K and Wistar rats, Charles River rats being 9 times less sensitive. The attenuation of the response 24 hr after 1 mg/kg 8-OH-DPAT measured as the shift in dose-response showed similar shift factors (4.1 to 6.7) for all rat colonies except for the B&K rats (3.0). The hypothermic response at 0.1 mg/kg 8-OH-DPAT was significantly lower for the Charles River and B&K rats than for the ALAB rats. Similarly was the maximal attenuation of the hypothermic effect in these rats less than half of that of the ALAB rats. The possible cause of the observed differences in the response to 8-OH-DPAT between these rat colonies is discussed in terms of receptor reserves and the involvement of other transmitter systems in the responses.

Selective effects on NGFI-A, MR, GR and NGFI-B hippocampal mRNA expression after chronic treatment with different subclasses of antidepressants in the rat.

There is a latency period of several weeks before the onset of clinical effect of antidepressant drugs. The detailed mechanisms underlying drug-induced adaptive neuronal changes are not known. To elucidate the involvement of changes in gene expression of candidate transcription factors, we treated rats for 21 days with buspirone, fluoxetine, 8-OH-DPAT and moclobemide. In situ hybridization was used to study mRNAs encoding NGFI-A, NGFI-B and the glucocorticoid receptors, MR and GR. NGFI-A mRNA expression increased profoundly in the hippocampal formation and the cerebral cortex after all drug treatments, especially after moclobemide treatment (77-122% increase); with the exception of buspirone. MR mRNA expression was induced in hippocampal CA1/CA2 subregions (27-37%) by all antidepressants, while moclobemide and 8-OH-DPAT significantly increased GR gene expression mainly in the CA1 region (31-44%). NGFI-B mRNA was significantly decreased in the hippocampal CA3 subfield (23%) and restrosplenial granular cortex (38%) by moclobemide treatment. There are selective effects of antidepressant drugs on specific transcription factors. These may be important for adaptive neuronal and neuroendocrine changes after antidepressant treatment including HPA axis negative feedback regulation.

Enhanced 5-HT metabolism and synthesis rate by the new selective r5-HT1B receptor antagonist, NAS-181 in the rat brain.

NAS-181 ((R)-(+)-2-(3-morpholinomethyl-2H-chromen-8-yl) oxymethyl-morpholine methanesulfonate) is a novel rat 5-hydroxytryptamine1B, (r5-HT1B) receptor antagonist with high selectivity. The in vivo effects of NAS-181 on 5-HT metabolism and synthesis in the rat brain were examined. 5-HT metabolism, measured as the ratio 5-hydroxyindoleacetic acid (5-HIAA)/5-HT, was dose-dependently increased in all four brain regions analysed (hypothalamus, hippocampus, frontal cortex and striatum) at doses 0.1 to 20 mg/kg s.c. NAS-181. The enhancement of 5-HT metabolism at the dose 20 mg/kg s.c. was maximal one hour after the injection and was still significant eight hours but not 24 hours after the injection. 5-HT synthesis rate measured as the accumulation of 5-hydroxytryptophan (5-HTP) after inhibition of the aromatic amino acid decarboxylase activity was also elevated by NAS-181 at doses 0.3 to 20 mg/kg s.c. NAS-181 competitively antagonised the decrease in 5-HT metabolism evoked by the r5-HT1B receptor agonist, anpirtoline, in hypothalamus, hippocampus and frontal cortex. Anpirtoline had no effect on 5-HT metabolism in striatum. However, anpirtoline antagonised the enhancement of 5-HT metabolism induced by NAS-181 in striatum. Combined treatment of rats with NAS-181 and the 5-HT1A receptor antagonist, WAY-100635, increased 5'-HT metabolism considerably more than when the compounds were given alone.

Increased dopaminergic and 5-hydroxytryptaminergic activities in male rat brain following long-term treatment with anabolic androgenic steroids.

1. The effects of treating groups of rats with four different anabolic androgenic steroids (AAS) (testosterone, nandrolone, methandrostenolone, and oxymetholone) on 5-hydroxytryptamine (5-HT) and dopamine (DA) neurones in different brain regions were examined. The AAS was injected six times with 1 week's interval and the rats were sacrificed 2 days after the final injection. 5-HT and its metabolite 5-hydroxyindoleacetic acid (5-HIAA), DA and its metabolites 3,4-dihydroxyphenylacetic acid (DOPAC) and homovanillic acid (HVA) were measured. The effect on DA and 5-HT synthesis rate was analysed as the accumulation of 3,4-dihydroxyphenyl-alanine (DOPA) and 5-hydroxytryptophan (5-HTP), respectively, after inhibition of the amino acid decarboxylase with NSD-1015 (3-hydroxy-benzylhydrazine dihydrochloride). Additionally, the monoamine oxidase (MAO) activity was analysed in the hypothalamus. 2. The DOPAC + HVA/DA ratio was increased in the striatum in all treatment groups. However, the synthesis rate of DA was significantly increased only in the methandrostenolone treated group. 3. The 5-HIAA/5-HT ratio was increased in all treatment groups in the hippocampus, in the frontal cortex in the methandrostenolone-treated animals and in the hypothalamus in the testosterone- and oxymetholone-treated rats, while the 5-HT synthesis rate was not affected by the AAS-treatments. 4. The MAO-A activity was increased in the oxymetholone-treated rats while the other treatment groups were unaffected. The MAO-B activity was not changed. 5. The results indicate that relatively high doses of AAS increase dopaminergic and 5-hydroxytryptaminergic metabolism in male rat brain, probably due to enhanced turnover in these monaminergic systems.

Synergism between 5-HT1B/1D and 5-HT1A receptor antagonists on turnover and release of 5-HT in guinea-pig brain in vivo.

The effects on 5-HT turnover (5-HIAA/5-HT ratio) and extracellular 5-HT and 5-HIAA levels (in vivo microdialysis in freely moving animals) were analysed in guinea-pig brains following the 5-HT1B receptor antagonist, GR 127935 [N-[4-methoxy-3-(4-methyl-1-piperazinyl)phenyl]-2'-methyl-4'-(5-methyl-1 ,2,4-oxadiazol-3-yl) [1,1-biphenyl]-4-carboxamide], or the 5-HT1A receptor antagonist, WAY-100635 (N-[2-[4-(2-methoxyphenyl)-1-piperazinyl]ethyl]-N-(2-pyridinyl) cyclohexanecarboxamide trihydrochloride), administered alone or in combination. GR 127935, injected alone, increased 5-HT turnover with maximal effects approximately 50% above the control levels in the four brain regions examined (hypothalamus, hippocampus, striatum and frontal cortex). GR 127935 significantly increased extracellular concentrations of 5-HT and 5-HIAA in frontal cortex (40%), whereas 5-HIAA, but not 5-HT, was elevated in striatum (20-30%). WAY-100635 did not significantly change 5-HT turnover but caused a small significant increase in the extracellular 5-HT and 5-HIAA concentrations in both striatum and frontal cortex. The combined treatment with GR 127935 and WAY-100635 resulted in an increased 5-HT turnover reaching maximal effects of 70-90% above the control values in all brain regions tested and produced a significant elevation of striatal and frontal cortex extracellular 5-HT (40% and 60%, respectively) and 5-HIAA (60% and 70%, respectively) concentrations. The synergistic effect of the two receptor antagonists on the 5-HT turnover and the terminal release of 5-HT indicate somatodendritic 5-HT release and stimulation of inhibitory 5-HT1A receptors at this level. Extracellular 5-HIAA seems to be a better marker than 5-HT itself for the evoked 5-HT release when the reuptake mechanism is intact.

Chronic amitriptyline treatment induces hippocampal NGFI-A, glucocorticoid receptor and mineralocorticoid receptor mRNA expression in rats.

Adult male rats were treated with the antidepressant drug amitriptyline for 21 days and the expression of specific transcription factors was examined. NGFI-A mRNA expression was increased in the hippocampus and in the cerebral cortex. MR mRNA was increased in the hippocampus while GR mRNA was increased in selective hippocampal regions. There was no change in the NGFI-B mRNA expression. Thus, NGFI-A may be a mediator of plasticity-related phenomena induced by antidepressant drugs.

In vivo labelling of the mouse brain 5-hydroxytryptamine1A receptor with the novel selective antagonist 3H-NAD-299.

The in vivo labelling of 5-hydroxytryptamine (5-HT)1A receptors in the mouse brain was studied with the novel selective 5-HT1A receptor antagonist, NAD-299 ((R)-3-N,N-dicyclobutylamino-8-fluoro-3,4-dihydro-2H-1-benzopyran- 5-carboxamide hydrogen (2R,3R)-tartrate monohydrate). 3H-NAD-299 was injected in a tail vein and the radioactivity in various brain regions was determined. More than 90% of the radioactivity in hippocampus, 15 min after the injection, was intact NAD-299. At this time the amount of 3H-NAD-299 was highest in hippocampus followed by frontal cortex, mesencephalon, hypothalamus, striatum and cerebellum. The specific accumulation of radioactivity (after subtracting cerebellum values) in frontal cortex and hippocampus was maximal 10 to 30 min after the injection and had almost disappeared after 2 h. Saturation kinetics derived Bmax (pmol/g wet weight tissue) values of 19.6+/-2.0 in frontal cortex and 38.0+/-3.5 in hippocampus. The apparent Kd values expressed in nmol/kg 3H-NAD-299 injected, were 12.3+/-2.2 in frontal cortex and 20.3+/-3.1 in hippocampus. The 5-HT1A receptor antagonist, WAY-100,635 competitively inhibited the specific accumulation of 3H-NAD-299 and was about equipotent with unlabelled NAD-299 with ED50 values of 20-30 nmol/kg s.c. These compounds were about 10 times more potent than the 5-HT1A receptor antagonists, p-MPPI and NDL-249 and 100 times more potent than (S)-UH-301. 5-HT1A receptor agonists, e.g. 8-OH-DPAT and flesinoxan and partial agonists, e.g. pindolol, buspirone and ipsapirone had low potency in this in vivo assay. Spiperone and methiothepin inhibited the 3H-NAD-299 accumulation at 10 micromol/kg s.c. The alpha1-adrenoceptor antagonist, prazosin at 2 micromol/kg s.c. increased significantly the specific accumulation of 3H-NAD-299. Pretreatment of the mice with the non-selective, irreversible receptor antagonist, EEDQ produced a dose related long-lasting decrease in the accumulation of 3H-NAD-299. It is concluded that NAD-299 is a very suitable ligand for studies of 5-HT1A receptors in the brain in vivo.

Differential regional antagonism of 8-OH-DPAT-induced decrease in serotonin synthesis by two 5-HT1A receptor antagonists.

The effects of two 5-HT1A receptor antagonists, (R)-3-N, N-dicyclobutylamino-8-fluoro-3,4-dihydro-2 H-1-benzopyran-5-carboxamide hydrogen (2 R,3 R)-tartrate monohydrate (NAD-299) and N-(2-(1-(2-methoxyphenyl)-piperazinyl))ethyl)-N-(2-pyridinyl) cyclohexanecarboxamide trihydrochloride (WAY-100635) on the decrease in 5-hydroxytryptophan (5-HTP) accumulation evoked by (RS)-2-dipropylamino-8-hydroxy-1,2,3,4-tetrahydronaphthalene (8-OH-DPAT) in rats treated with the decarboxylase inhibitor, 3-hydroxyphenylhydrazine (NSD 1015) were studied in four rat brain regions: hippocampus, hypothalamus, striatum and frontal cortex. Dose-response studies revealed differential effects of both antagonists in the areas examined. Both antagonists were significantly more potent in antagonising the effect of 0.30 and 0.76 micromol/kg s.c. 8-OH-DPAT in hippocampus than in hypothalamus, striatum and frontal cortex in mentioned order. This order of potency was the opposite to that found for 8-OH-DPAT in decreasing the 5-HTP accumulation. Since previous studies by others have indicated that the reserve of somatodendritic 5-HT1A receptors is greater in dorsal raphe nucleus innervating frontal cortex and striatum than in median raphe nucleus which mainly innervates hippocampus, the observed different regional potency of the two 5-HT1A receptor antagonists may be explained by this difference in the 5-HT1A receptor reserve.

(R)-(+)-2-[[[3-(Morpholinomethyl)-2H-chromen-8-yl]oxy]methyl] morpholine methanesulfonate: a new selective rat 5-hydroxytryptamine1B receptor antagonist.

In the search for new 5-hydroxytryptamine (5-HT) receptor antagonists it was found that the compound (R)-(+)-2-[[[3-(morpholinomethyl)-2H-chromen-8-yl]oxy] methyl] morpholine methanesulfonate, (R)-25, is a selective rat 5-hydroxytryptamine1B (r5-HT1B) receptor antagonist. The binding profile showed a 13-fold preference for r5-HT1B (Ki = 47 +/- 5 nM; n = 3) vs bovine 5-HT1B (Ki = 630 nM; n = 1) receptors. The compound had very low affinity for other monoaminergic receptors examined. The r5-HT1B receptor antagonism was demonstrated by the potentiation of the K+-stimulated release of [3H]-5-HT from superfused rat brain slices in vitro, an effect that was antagonized by addition of 5-HT to the superfusion fluid. (R)-25 at 20 mg/kg sc enhanced the 5-HT turnover in four rat brain regions (hypothalamus, hippocampus, striatum, and frontal cortex) with about 40% measured as the 5-HTP accumulation after decarboxylase inhibition with 3-hydroxybenzylhydrazine. At 3 mg/kg sc (R)-25 produced a significant increase in the number of wet dog shakes in rats, a 5-HT2A/5-HT2C response that was abolished by depletion of 5-HT after pretreatment with the tryptophan hydroxylase inhibitor p-chlorophenylalanine. These observations show that (R)-25, by inhibiting terminal r5-HT1B autoreceptors, increases the 5-HT turnover and the synaptic concentration of 5-HT.

The pharmacological characterization of a novel selective 5-hydroxytryptamine1A receptor antagonist, NAD-299.

The pharmacological properties of a novel selective 5-hydroxytryptamine1A (5-HT1A) receptor antagonist, NAD-299 [(R)-3-N,N-dicyclobutylamino-8-fluoro-3,4-dihydro-2H-1-benzopyran-5-carboxamide hydrogen (2R,3R)-tartrate monohydrate] were examined in vitro and in vivo and compared with the reference 5-HT1A receptor antagonist, WAY-100635 [N-(2-(1-(4-(2-methoxyphenyl)piperazin-yl))ethyl)-N-(2-pyridinyl) cyclohexanecarboxamide trihydrochloride]. The new compound had high affinity for 5-HT1A receptors in vitro with a Ki value of 0.6 nM. The only other receptors for which NAD-299 had affinity less than 1 microM were alpha-1 and beta adrenoceptors with Ki values of 260 and 340 nM, respectively. Thus, the selectivity of NAD-299 for 5-HT1A receptors was more than 400 times. WAY-100635 had considerably higher affinity than NAD-299 for alpha-1 adrenoceptors (Ki = 45 nM) and dopamine D2 and D3 receptors (Ki = 79 and 67 nM, respectively). Like WAY-100635, NAD-299 competitively blocked 5-HT-induced inhibition of vasoactive intestinal peptide-stimulated cAMP production in GH4ZD10 cells and had no intrinsic activity. Both compounds were therefore 5-HT1A receptor antagonists in vitro and also behaved as such in in vivo experiments. Thus, they competitively antagonized the 8-hydroxy-2-(di-n-propylamino)tetralin-induced 5-HT behavioral effects, hypothermia, corticosterone secretion and inhibition of passive avoidance behavior without causing any actions of their own. The effective dose of NAD-299 varied between 0.03 and 0.35 micromol/kg s.c., depending on the test and the dose of 8-hydroxy-2-(di-n-propylamino)tetralin.

NMDA receptor-mediated increase in cyclic GMP in the rat cerebellum in vivo is blocked by alaproclate and GEA-857.

The effects of alaproclate and GEA-857 (2-(4-chlorophenyl)-1,1-dimethylethyl 2-amino-3-methylbutanoate) on the production of cyclic GMP in the rat cerebellum in vivo induced by stimulation of N-methyl-D-aspartate (NMDA) receptors were studied. Alaproclate per se at a dose of 20 mg/kg subcutaneously, did not influence the basal cGMP level. The increase in cGMP induced by harmaline (20 mg/kg subcutaneously) was dose-dependently antagonized by alaproclate (5-40 mg/kg subcutaneously). S-(-)-Alaproclate was 2-5 times more potent than the R-(+)-enantiomer. GEA-857 which in contrast to alaproclate is a very weak 5-HT uptake inhibitor shared the ability of alaproclate to inhibit the effect of harmaline on cGMP accumulation with similar potency to S-(-)-alaproclate. Alaproclate at 15 mg/kg subcutaneously blocked the increase in cGMP in cerebellum caused by NMDA itself at 200 mg/kg subcutaneously. In contrast to alaproclate, the K+ channel antagonist, 4-aminopyridine, 5 mg/kg subcutaneously, produced per se an increase in cGMP levels in the rat cerebellum by 300% which was antagonized by the NMDA receptor antagonists, dizocilpine, phencyclidine and (+/-)-CCP, the nitric oxide synthase inhibitor, NG-nitro-L-arginine methyl ester and by alaproclate. Alaproclate. Alaproclate and GEA-857 antagonized seizures induced by NMDA, 200 mg/kg subcutaneously at doses similar to those antagonizing the harmaline- and NMDA-induced elevation of cerebellar cGMP. Neither alaproclate nor GEA-857 caused any behavioural effects typical for uncompetitive NMDA receptor antagonists except a slight increase in motor activity and sniffing. The effect of alaproclate on the NMDA receptor-mediated increase in cGMP in rat cerebellum in vivo might be due to blockade of the cation channel of the NMDA receptor complex previously observed in in vitro experiments and these compounds seems to belong to the group of low-affinity uncompetitive NMDA receptor antagonists that might have clinical interest.

Neurologic Manifestationsof HIV Infection Without AIDS:Follow-UP of a Cohortof Homosexual and Bisexual Men.

To identify neurological abnormalities in HIV infection, 159 HIV-seropositive men without AIDS and 76 seronegative controls underwent standardized general and neurological examinations, lumbar puncture (LP), neuropsychological (NP) assessment, and brain magnetic resonance (MR) imaging. History, physical, and laboratory evaluations were repeated every six months. NP tests (all subjects) and MR imaging (seropositives only) was repeated every 6-12 months; LP (seropositives only) was repeated yearly. Mean follow-up was 24.6 months. Neurological abnormalities, most related to hearing, were seen in 60 (38.2%) of 157 seropositives and 23 (30.3%) of 76 controls at baseline (p = NS). During follow-up, 43 (31.6%) of 136 seropositives had persistent hearing abnormalities compared to 9 (14.1%) of 64 seronegatives (p = 0.008). Seven HIV-seropositives developed peripheral neuropathy; this was more common among those with hearing abnormalities (p = 0.03). HIV-seropositives performed less well on NP tests than controls, but overall performance did not decline. Worsening brain atrophy by MR imaging or cerebrospinal fluid abnormalities are more common in HIV-seropositives than seronegatives and may share a common mechanism with peripheral neuropathy. Further study is needed to determine whether these abnormalities portend more serious neurological disease.

[3H]WIN 35,428 binding in the human brain.

The binding of [3H]WIN 35,428 was studied in post-mortem human brain, including extrastriatal regions. In the putamen, dopamine almost completely inhibited the [3H]WIN 35,428 binding. Paroxetine inhibited the binding with similar affinity as cocaine, in the range 200-300 nM. In the frontal cortex, [3H]WIN 35,428 labelled cocaine- and alaproclate sensitive binding sites, of which a major fraction was of protein nature. The elucidation of the cocaine sensitive sites in the frontal cortex should be the subject of further research.