1
|
Saunders C, Siuta M, Robertson SD, Davis AR, Sauer J, Matthies HJG, Gresch PJ, Airey D, Lindsley CW, Schetz JA, Niswender KD, Veenstra-Vanderweele JM, Galli A. Neuronal ablation of p-Akt at Ser473 leads to altered 5-HT1A/2A receptor function. Neurochem Int 2013; 73:113-121. [PMID: 24090638 DOI: 10.1016/j.neuint.2013.09.015] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2013] [Revised: 09/16/2013] [Accepted: 09/19/2013] [Indexed: 02/08/2023]
Abstract
The serotonergic system regulates a wide range of behavior, including mood and impulsivity, and its dysregulation has been associated with mood disorders, autism spectrum disorder, and addiction. Diabetes is a risk factor for these conditions. Insulin resistance in the brain is specifically associated with susceptibility to psychostimulant abuse. Here, we examined whether phosphorylation of Akt, a key regulator of the insulin signaling pathway, controls serotonin (5-HT) signaling. To explore how impairment in Akt function regulates 5-HT homeostasis, we used a brain-specific rictor knockout (KO) mouse model of impaired neuronal phosphorylation of Akt at Ser473. Cortical 5-HT1A and 5-HT2A receptor binding was significantly elevated in rictor KO mice. Concomitant with this elevated receptor expression, the 5-HT1A receptor agonist 8-Hydroxy-2-(di-n-propylamino)tetralin (8-OH-DPAT) led to an increased hypothermic response in rictor KO mice. The increased cortical 5-HT1A receptor density was associated with higher 5-HT1A receptor levels on the cortical cell surface. In contrast, rictor KO mice displayed significantly reduced head-twitch response (HTR) to the 5-HT2A/C agonist 2,5-dimethoxy-4-iodoamphetamine (DOI), with evidence of impaired 5-HT2A/C receptor signaling. In vitro, pharmacological inhibition of Akt significantly increased 5-HT1A receptor expression and attenuated DOI-induced 5-HT2A receptor signaling, thereby lending credence to the observed in vivo cross-talk between neuronal Akt signaling and 5-HT receptor regulation. These data reveal that defective central Akt function alters 5-HT signaling as well as 5-HT-associated behaviors, demonstrating a novel role for Akt in maintaining neuronal 5-HT receptor function.
Collapse
Affiliation(s)
- Christine Saunders
- Department of Pharmacology, Vanderbilt University Medical Center, Nashville, TN
| | - Michael Siuta
- Department of Molecular Physiology and Biophysics, Vanderbilt University Medical Center, Nashville, TN
| | - Sabrina D Robertson
- Department of Molecular Physiology and Biophysics, Vanderbilt University Medical Center, Nashville, TN
| | - Adeola R Davis
- Department of Molecular Physiology and Biophysics, Vanderbilt University Medical Center, Nashville, TN
| | - Jennifer Sauer
- Department of Psychiatry, Vanderbilt University Medical Center, Nashville, TN
| | - Heinrich J G Matthies
- Department of Molecular Physiology and Biophysics, Vanderbilt University Medical Center, Nashville, TN
| | - Paul J Gresch
- Department of Pharmacology, Vanderbilt University Medical Center, Nashville, TN
| | - David Airey
- Department of Pharmacology, Vanderbilt University Medical Center, Nashville, TN
| | - Craig W Lindsley
- Department of Pharmacology, Vanderbilt University Medical Center, Nashville, TN
| | - John A Schetz
- Department of Pharmacology & Neuroscience, University of North Texas Health Science Center, Fort Worth, TX
| | - Kevin D Niswender
- Department of Medicine Vanderbilt University Medical Center, Nashville, TN
| | - Jeremy M Veenstra-Vanderweele
- Department of Pharmacology, Vanderbilt University Medical Center, Nashville, TN.,Department of Psychiatry, Vanderbilt University Medical Center, Nashville, TN
| | - Aurelio Galli
- Department of Molecular Physiology and Biophysics, Vanderbilt University Medical Center, Nashville, TN.,Department of Neuroscience Program in Substance Abuse, Vanderbilt University Medical Center, Nashville, TN
| |
Collapse
|
2
|
Zhuang ZP, Kung MP, Mu M, Kung HF. Isoindol-1-one analogues of 4-(2'-methoxyphenyl)-1-[2'-[N-(2"-pyridyl)-p-iodobenzamido]ethyl]pipera zine (p-MPPI) as 5-HT1A receptor ligands. J Med Chem 1998; 41:157-66. [PMID: 9457239 DOI: 10.1021/jm970296s] [Citation(s) in RCA: 125] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
In developing radioiodinated antagonists for in vivo imaging of 5-HT1A receptors with SPECT, a series of new arylpiperazine benzamido derivatives, including 4-(2'-methoxyphenyl)-1-[2'-[N-(2"-pyridyl)-p-iodobenzamido]ethyl]p iperazine (p-MPPI, 31) (Kd = 0.36 nM), as potential ligands for 5-HT1A receptors were reported previously. However, rapid in vivo metabolism may have caused the breakdown of the amide bond of [123I]-31 and rendered this agent obsolete as an in vivo imaging agent in humans. To improve the in vivo stability of 31, a series of cyclized amide analogues were designed and synthesized. In vitro binding, metabolic stability, and in vivo biodistribution of these new derivatives were investigated. Several five-membered-ring isoindol-1-ones displayed very high in vitro binding affinity, especially 2-{2-[4-(2-methoxyphenyl)piperazin-1-yl]ethyl}-6-nitro-3-phenyl-2, 3-dihydroisoindol-1-one, 15, 3-hydroxy-6-iodo-2-{2-[4-(2-methoxyphenyl)piperazin-1-yl]ethyl}- 3- phenyl-2,3-dihydroisoindol-1-one, 18, and 6-iodo-2-{2-[4-(2-methoxyphenyl)piperazin-1-yl]ethyl}-3-phenyl-2, 3-dihydroisoindol-1-one, 21, which showed Ki values of 0.05, 0.65, and 0.07 nM, respectively. The affinities for 5-HT1A receptors of other cyclized amide derivatives, 5-(4-bromophenyl)-1-{2-[4-(2-methoxyphenyl)- piperazin-1-yl]ethyl}pyrrolidin-2-one, 25, 5-(4-iodophenyl)-1-{2-[4-(2-methoxyphenyl)piperazin- 1-yl]ethyl}pyrrolidin-2-one, 27, and 2-{2-[4-(2-methoxyphenyl)piperazin-1-yl]ethyl}-2,3-dihydro- isoindol-1-one, 29, were 1.09, 2.54, and 14.9 nM, respectively. Compared to [125I]-31, iodinated cyclized amide derivatives [125I]-21 and [125I]-27 displayed a slower metabolism in human liver microsomal and cytosolic preparations. Biodistribution of [125I]-21 and [125I]-27 in rats (after an i.v. injection) displayed moderate to low brain uptakes with little or no specific localization in hippocampal region, where 5-HT1A receptors are concentrated. These data indicate that the new iodinated ligands showed high binding affinities and better metabolic stability but displayed unexpectedly low selective binding to 5-HT1A receptors in vivo. Additional structural modifications may be needed to correct the unfavorable properties displayed for these iodinated cyclized amide derivatives for in vivo biodistribution in rats.
Collapse
Affiliation(s)
- Z P Zhuang
- Department of Radiology, University of Pennsylvania, Philadelphia 19104, USA
| | | | | | | |
Collapse
|
3
|
Meyniel JP, Khan NA, Ferrière F, Deschaux P. Identification of lymphocyte 5-HT3 receptor subtype and its implication in fish T-cell proliferation. Immunol Lett 1997; 55:151-60. [PMID: 9161881 DOI: 10.1016/s0165-2478(97)02697-7] [Citation(s) in RCA: 24] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
In the present study, we identified the serotonergic receptor of type 3 (5-HT3) on the lymphocytes of a teleost fish, Oncorhynchus mykiss. In the pharmacological studies on the binding of [3H]serotonin to membrane receptor sites, 2-methyl-5-HT, an agonist of 5-HT3 receptors, displaced the binding of [3H]serotonin to fish lymphocytes, indicating the presence of 5-HT3 receptors on these cells. The known antagonists of the mammalian 5-HT3 receptor, ICS-205-930 and metoclopramide, failed to displace [3H]serotonin binding to lymphocytes during the period of association equilibrium (8 min); however, these antagonists progressively displaced [3H]serotonin binding from 10 to 40 min of incubation. These results suggest that fish 5-HT3 lymphocyte receptors may differ pharmacologically from mammalian receptors. As mammalian 5-HT3 receptors are coupled with Na+ inward movements, we undertook a study on Na+ influx by using SBFI/AM, a fluorescent probe. In SBFI/AM loaded fish lymphocytes, 2-methyl-5-HT leaked Na+ inward movements. Prior incubation of lymphocytes for 30 min in the presence of 5-HT3 antagonists, ICS-205-930, metoclopramide and MDL-72222, curtailed significantly the Na+ influx evoked by 2-methyl-5-HT, demonstrating that Na+ is leaked into fish lymphocytes via the 5-HT3 receptor-channel whose functioning is blocked by these antagonists. Furthermore, 2-methyl-5-HT exerted immunosuppressive effects in a dose dependent manner on fish T-lymphocytes stimulated by phytohaemagglutinin (PHA). Serotonin and 2-methyl-5-HT blocked the cell cycle progression of PHA-stimulated T-cells from G0/G1 to S phase. The immunosuppressive effects of 2-methyl-5-HT on T-cells were partially reversed by the antagonists, metoclopramide and ICS-205-930; however, the latter antagonist at high concentrations synergized with the immunosuppressive effects of 2-methyl-5-HT. These results demonstrate that the fish lymphocyte 5-HT3 receptor, which may be pharmacologically different from mammalian receptor subtype, is functionally implicated in fish T-cell proliferation.
Collapse
Affiliation(s)
- J P Meyniel
- Laboratoire de Physiologie Animale, Faculté des Sciences de Limoges, France
| | | | | | | |
Collapse
|
4
|
Abstract
We studied the effects of buspirone and 8-hydroxy-2-(di-n-propylamino) tetralin (8-OH-DPAT) on duration of immobility in mice in the forced swim test. Buspirone [3-10 mg/kg, intraperitoneally (IP)] potently and dose dependently increased the duration of immobility in mice. In contrast, following a single dose of 8-OH-DPAT (1-3 mg/kg, IP), there was a dose-dependent decrease in the duration of immobility. Pretreatment with the 5-HT synthesis inhibitor p-chlorophenylalanine (200 mg/kg, IP, 3 days before further drug treatment) did not alter the effects of buspirone or 8-OH-DPAT. The increase in the duration of immobility induced by buspirone (3 mg/kg, IP) was blocked by NAN-190 [1-(2-methoxyphenyl)-4-(4-[2-phthalimido]butyl)-piperazine hydrobromide, 1 mg/kg, IP], a postsynaptic 5-HT1A receptor antagonist. However, the effect of 8-OH-DPAT (1 mg/kg, IP) was not blocked by NAN-190 (1 mg/kg, IP). The effect of buspirone (3 mg/kg, IP) was blocked by apomorphine (0.3 mg/kg, IP), a dopamine receptor agonist. Based on the results of this study, it is suggested that the effects of buspirone and of 8-OH-DPAT on immobility in the forced swim test may occur through different mechanisms.
Collapse
Affiliation(s)
- Y Kitamura
- Laboratory for Pharmacology, Asahi Chemical Industry Co., Ltd., Shizuoka, Japan
| | | |
Collapse
|
5
|
Powell KR, Dykstra LA. The role of serotonergic receptors in the effects of mu opioids in squirrel monkeys responding under a titration procedure. Psychopharmacology (Berl) 1996; 126:42-9. [PMID: 8853215 DOI: 10.1007/bf02246409] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
This experiment was conducted to determine whether drugs acting on brain serotonin modulate the effects of the mu opioid, morphine, as measured by the squirrel monkey shock titration procedure and, if so, whether serotonergic modulation is mediated via specific 5HT receptor subtypes. Under this procedure, electric shock was delivered to the monkey's tail and scheduled to increase once every 15 s from 0.01 to 2.0 mA in 30 steps. Five responses on a lever during the 15-s shock period terminated the shock for 15 s, after which the shock resumed at the next lower intensity. The intensity below which monkeys maintained shock 50% of the time (median shock level or MSL) and rate of responding (RR) in the presence of shock were determined under control conditions and after administration of morphine alone and in combination with various serotonergic compounds. Morphine increased median shock level and decreased rate of responding in a dose-dependent manner. These effects of morphine was attenuated by the 5HT1A receptor agonists, 8-OH-DPAT [(+)-8-hydroxy-2(di-n-propylamino tetralin HBr] and ipsapirone. The effects of morphine were not altered by the 5HT1A receptor antagonist, NAN-190 [1-(2-methoxyphenyl-4-[4-(2-phthalimido) butyl] piperazine HBr], and 5HT2 receptor antagonist, ketanserin, the 5HT3 receptor antagonist, MDL 72222 [3-tropanyl-3,5-dichlorobenzoate], the alpha 2 adrenergic antagonist, yohimbine, or the alpha2 adrenergic agonist, clonidine. These results suggest that 5HT1A receptors may be involved in the effects of morphine in the shock titration procedure, whereas 5HT2, 5HT3 and alpha 2 adrenergic receptors do not appear to play a role in morphine's effects in this procedure.
Collapse
Affiliation(s)
- K R Powell
- Department of Psychology, University of North Carolina at Chapel Hill 27599-3270, USA
| | | |
Collapse
|
6
|
Bjørkum AA, Ursin R. Sleep/waking effects following intrathecal administration of the 5-HT(1A) Agonist 8-OH-DPAT alone and in combination with the putative 5-HT(1A) antagonist NAN-190 in rats. Brain Res Bull 1996; 39:373-9. [PMID: 9138747 DOI: 10.1016/0361-9230(96)00029-9] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Sleep, waking, and EEG power spectra were investigated in rats after intrathecal (IT) administration of a 5-HT(1A) agonist and a 5-HT(1A) antagonist. Total slow wave sleep (TSWS) was increased and waking was decreased over the 8-h recording period after the 5-HT(1A) agonist 8-hydroxy-2-(di-n-propylamino)tetralin (8-OH-DPAT) (38 nmol). Within TSWS, SWS1 was unchanged while SWS-2 tended to be increased. The 5-HT(1A) antagonist 1-[2-Methoxyphenyl)-4-(4-(2-phthalimido)-butyl]piperazine hydrobromide (NAN-190) did not change any sleep/waking stages. Combined treatment with 8-OH-DPAT and NAN-190 increased variance. Following the combination, sleep and waking were not significantly different from control. SWS-2 tended to be reduced compared to the effect of 8-OH-DPAT alone. There were no systematic changes in neither waking nor TSWS fronto-frontal or fronto-parietal EEG power spectrum after any of the treatments, indicating that sleep quality was not changed. The results confirm earlier data suggesting that in the spinal cord, stimulation of 5-HT(1A) receptors have a dampening effect on transmission of sensory information, leading to deactivation and thereby increased sleep tendency. The reason why the 8-OH-DPAT effect was not clearly antagonized by the putative 5-HT1A antagonist NAN-190, may be due to the generally weak antagonistic and also partial agonistic effect of NAN-190 as reported in the literature.
Collapse
Affiliation(s)
- A A Bjørkum
- Department of Physiology, University of Bergen, Norway
| | | |
Collapse
|
7
|
Groenink L, Van der Gugten J, Mos J, Maes RA, Olivier B. The corticosterone-enhancing effects of the 5-HT1A receptor antagonist, (S)-UH301, are not mediated by the 5-HT1A receptor. Eur J Pharmacol 1995; 272:177-83. [PMID: 7713161 DOI: 10.1016/0014-2999(94)00645-n] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
We tried to antagonize the endocrine and behavioural changes induced by the selective 5-HT1A receptor agonist, flesinoxan, with the putative 5-HT1A receptor antagonist, (S)-UH301 ((S)-5-fluoro-8-hydroxy-2-(di-n-propylamino)tetralin). The interaction of (S)-UH301 (3 and 10 mg/kg s.c.) with flesinoxan (3 mg/kg s.c.) showed no antagonistic effects of (S)-UH301 on flesinoxan-induced corticosterone secretion. In fact, like flesinoxan (1 and 3 mg/kg s.c.), (S)-UH301 (3 and 10 mg/kg s.c.) itself dose dependently increased plasma corticosterone levels. Unlike flesinoxan, (S)-UH301 did not induce hyperglycemia, lower lip retraction and flat body posture. Moreover, flesinoxan-induced hyperglycemia and behavioural changes were effectively antagonized by (S)-UH301, showing potent 5-HT1A receptor antagonistic effects of (S)-UH301. Therefore we conclude that (S)-UH301 is a potent 5-HT1A receptor antagonist and that the (S)-UH301-induced corticosterone secretion is mediated by a non-5-HT1A receptor mechanism.
Collapse
Affiliation(s)
- L Groenink
- Department of Psychopharmacology, Rudolf Magnus Institute for Neurosciences, Utrecht University, Netherlands
| | | | | | | | | |
Collapse
|
8
|
Berendsen HH, Bourgondien FG, Broekkamp CL. Role of dorsal and median raphe nuclei in lower lip retraction in rats. Eur J Pharmacol 1994; 263:315-8. [PMID: 7843270 DOI: 10.1016/0014-2999(94)90728-5] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Induction of lower lip retraction after local infusion of the selective 5-HT1A receptor agonist (+/-)-8-hydroxy-2-(di-n-propylamino)tetralin (8-OH-DPAT) in the dorsal and median raphe nuclei was measured. Infusion of 8-OH-DPAT (2.5, 5 and 10 micrograms/rat) into the median raphe nucleus caused an immediate and dose-dependent lower lip retraction. After infusion into the dorsal raphe nucleus a higher dose was needed. The lowest dose of 8-OH-DPAT that induced lower lip retraction was 10 micrograms/rat. Infusion of 8-OH-DPAT (10 micrograms/rat) into the pontine reticular nucleus induced the same degree of lower lip retraction as seen after infusion of the compound into the dorsal raphe nucleus. 8-OH-DPAT-induced lower lip retraction was attenuated by s.c. injection of the preferential 5-HT2C receptor agonist m-chlorophenyl-piperazine. The results suggest that lower lip retraction is mediated by 5-HT1A receptors in the median rather than in the dorsal raphe nucleus.
Collapse
Affiliation(s)
- H H Berendsen
- Department of Neuropharmacology, N.V. Organon, Oss, Netherlands
| | | | | |
Collapse
|
9
|
Przegaliński E, Tatarczyńska E, Kłodzińska A, Chojnacka-Wójcik E. The role of postsynaptic 5-HT1A receptors in the anticonflict effect of ipsapirone. Neuropharmacology 1994; 33:1109-15. [PMID: 7838324 DOI: 10.1016/0028-3908(94)90150-3] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
In the present paper we have studied the anticonflict effect (in the Vogel test) of ipsapirone, a partial agonist of 5-hydroxytryptamine1A (5-HT1A) receptors, administered to the hippocampus of rats. In addition, a comparison of the effect of ipsapirone with the effect of other 5-HT1A receptor ligands (busipone, gepirone and 8-OH-DPAT) has been carried out. Finally, the interaction between ipsapirone and NAN-190 (an antagonist of 5-HT1A receptors and alpha 1-adrenoceptors) has also been examined. It has been found that ipsapirone injected intrahippocampally (i.hp.) in doses of 0.3, 1 and 3 micrograms (bilaterally) shows an anticonflict effect by increasing the number of punished licks by about 36, 151 and 109%, respectively. A similar effect has also been found after i.hp. injections of buspirone (0.3-3 micrograms), gepirone (3-30 micrograms) and 8-OH-DPAT (0.3-3 micrograms). We have also demonstrated that the anticonflict effect of ipsapirone injected i.hp. is antagonized by NAN-190 administered i.hp. (0.3 or 1 microgram) or intraperitoneally (i.p., 1 mg/kg). Furthermore, NAN-190 injected i.hp. (0.3 microgram) antagonizes the anticonflict effect of ipsapirone administered i.p. (5 mg/kg). At the same time, the anticonflict effects of ipsapirone are not affected by prazosin (0.3-1 microgram i.hp. or 0.5-1 mg/kg i.p.), a selective antagonist of alpha 1-adrenoceptors. Our results seem to indicate that the anticonflict effect of ipsapirone stems from stimulation of postsynaptic 5-HT1A receptors in the hippocampus.
Collapse
Affiliation(s)
- E Przegaliński
- Institute of Pharmacology, Polish Academy of Sciences, Kraków
| | | | | | | |
Collapse
|
10
|
Ybema CE, Slangen JL, Olivier B. Discriminative stimulus effect of flesinoxan: effect of 5-HT1A antagonists and PCPA. Pharmacol Biochem Behav 1994; 47:957-62. [PMID: 8029269 DOI: 10.1016/0091-3057(94)90303-4] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Rats were trained to discriminate 0.3 mg/kg (IP) flesinoxan from saline in a standard two-lever operant procedure and thereafter subjected to generalization and antagonism tests with the 5-HT1A receptor agonist ipsapirone and the beta-adrenergic/5-HT1 receptor antagonist pindolol. Ipsapirone (3.0 mg/kg) completely substituted for flesinoxan. Both the flesinoxan (0.3 mg/kg) and the ipsapirone cue (3.0 mg/kg) were dose-dependently blocked by (+/-)-pindolol. In a second group of rats, trained to discriminate 0.5 mg/kg (IP) of flesinoxan from saline, the putative 5-HT1A antagonist NAN-190 (in the dose range of 1.0 to 6.0 mg/kg) partially blocked the cue of flesinoxan. Generalization studies revealed that the flesinoxan cue could not be mimicked by NAN-190 (3.0 mg/kg). Finally, rats were pretreated with the 5-HT depletor parachlorophenylalanine (PCPA) and thereafter tested with the flesinoxan training dose (0.5 mg/kg). PCPA pretreatment did not significantly attenuate the recognition of the flesinoxan cue. The present results are in agreement with previous findings concerning the stimulus effect of flesinoxan and point to a mechanism that involves the activation of 5-HT1A receptors in the brain. Depletion of 5-HT did not significantly affect the stimulus effect of flesinoxan, suggesting that presynaptic 5-HT1A receptors do not play a crucial role in the mechanism underlying the stimulus effect of flesinoxan.
Collapse
Affiliation(s)
- C E Ybema
- Department of Psychopharmacology, Faculty of Pharmacy, Utrecht University, The Netherlands
| | | | | |
Collapse
|
11
|
Critchley DJ, Middlefell VC, Liddle CW, Foden ND, Dourish CT. Effects of the selective 5-HT1A receptor antagonist WAY100135 and its enantiomers on 8-OH-DPAT-induced hyperglycaemia in conscious rats. Eur J Pharmacol 1994; 254:133-9. [PMID: 8206109 DOI: 10.1016/0014-2999(94)90380-8] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
8-Hydroxy-2-(di-n-propylamino)tetralin (8-OH-DPAT) increases plasma glucose levels in conscious rats probably by stimulation of central 5-HT1A receptors. We have examined the effects of WAY100135 (N-tert-butyl-3-[4-(2-methoxyphenyl)piperazin-1-yl]-2-phenylpropan amide), a selective 5-HT1A receptor antagonist and its enantiomers on plasma glucose levels and on the hyperglycaemia induced by 8-OH-DPAT. (R,S)-WAY100135 (minimum effective dose (MED) 3 mg/kg i.v.) and (S)-WAY100135 (MED 1 mg/kg i.v.) dose-dependently attenuated 8-OH-DPAT-induced hyperglycaemia. In contrast, (R)-WAY100135 at doses up to 3 mg/kg i.v. was unable to block hyperglycaemia induced by 8-OH-DPAT. When the antagonists were examined for intrinsic effects on plasma glucose levels only (S)-WAY100135 (3 mg/kg i.v.) caused a significant but transient hyperglycaemia (20% increase). These results are consistent with previous suggestions that (R,S)-WAY100135 and (S)-WAY100135 are selective 5-HT1A receptor antagonists and that 8-OH-DPAT-induced hyperglycaemia is mediated by 5-HT1A receptors. The antagonist action of WAY100135 is stereoselective, and more potent activity being observed with the (S) enantiomer.
Collapse
Affiliation(s)
- D J Critchley
- Department of Neuropharmacology, Wyeth Research (UK) Ltd., Maidenhead, Berkshire, UK
| | | | | | | | | |
Collapse
|
12
|
Moore NA, Rees G, Sanger G, Perrett L. 5-HT1A-mediated lower lip retraction: effects of 5-HT1A agonists and antagonists. Pharmacol Biochem Behav 1993; 46:141-3. [PMID: 8255903 DOI: 10.1016/0091-3057(93)90330-v] [Citation(s) in RCA: 28] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
This study investigated the production of lower lip retraction (LLR) in the rat by the 5-hydroxytryptamine1A (5-HT1A) agonist 8-hydroxy-2-(di-n-propylamino)-tetralin (8-OH-DPAT) and the effect of the putative 5-HT1A antagonists pindolol and (1-(2-methoxy-phenyl)-4-[4-(2-phthalimido)-butyl]-piperazine (NAN190). 8-OH-DPAT (0.125-1.0 mg/kg, IP) caused a dose-related increase in LLR. Pindolol (10-40 mg/kg, IP) and NAN190 (2.5-10 mg/kg, IP) produced a dose-related block of 8-OH-DPAT-induced LLR. Pindolol (10-40 mg/kg, IP) when administered alone was also found to cause LLR, suggesting that pindolol behaves as a partial agonist in this model. This was not the case with NAN190 (2.5-10 mg/kg, IP), which failed to produce LLR; however, NAN190 (2.5-10 mg/kg, IP) produced a dose-related block of the pindolol-induced LLR. These results clearly demonstrate that the LLR model can be used to detect 5-HT1A agonists, partial agonists, and antagonists.
Collapse
Affiliation(s)
- N A Moore
- Lilly Research Centre, Eli Lilly & Co., Windlesham, Surrey, UK
| | | | | | | |
Collapse
|
13
|
Abstract
Stimulus control was established in rats using either 8-hydroxy-2-[di-n-propylamino]tetralin (DPAT) (0.2 mg/kg) or yohimbine (3 mg/kg). Tests were then conducted with purported antagonists at 5-hydroxytryptamine1A (5-HT1A) receptors. Drugs studied were NAN-190, [+/-]-pindolol, and [-]-alprenolol. In addition, each drug was characterized in terms of its affinity for 5-HT1A and alpha 2-adrenoceptors by means of radioligand binding techniques. None of the antagonists tested provided complete blockade of the stimulus effects of either DPAT or yohimbine. However, [+/-]-pindolol produced a statistically significant intermediate degree of antagonism of both DPAT and yohimbine. The affinities of DPAT, yohimbine, and NAN-190 for the 5-HT1A and alpha 2-adrenergic receptors, respectively, were sufficiently high to lead to some ambiguity of interpretation of the behavioral data. However, the results with [+/-]-pindolol, which has high affinity for the 5-HT1A receptor (34 nM) and negligible affinity for the alpha 2-adrenoceptor (24,600 nM), indicate that a significant component of yohimbine-induced stimulus control is mediated by the 5-HT1A receptor.
Collapse
Affiliation(s)
- J C Winter
- Department of Pharmacology and Therapeutics, School of Medicine and Biomedical Sciences, State University of New York, Buffalo 14214
| | | |
Collapse
|
14
|
Schoeffter P, Fozard JR, Stoll A, Siegl H, Seiler MP, Hoyer D. SDZ 216-525, a selective and potent 5-HT1A receptor antagonist. Eur J Pharmacol 1993; 244:251-7. [PMID: 8384569 DOI: 10.1016/0922-4106(93)90150-8] [Citation(s) in RCA: 48] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
The pharmacological properties of SDZ 216-525, methyl 4-(4-[4-(1,1,3-trioxo-2H-1,2-benzoisothiazol-2-yl)butyl]-1-p iperazinyl)1H- indole-2-carboxylate, a new selective and potent 5-HT1A receptor antagonist, are described in vitro (and comparisons made with those of MDL 73005 and NAN 190, two putative 5-HT1A receptor antagonists) and in vivo. In radioligand binding studies, SDZ 216-525 showed high affinity and selectivity for 5-HT1A sites (pKD = 9.2) as compared to 5-HT1B, 5-HT1C, 5-HT1D, 5-HT2 and 5-HT3 sites (pKD = 6.0, 7.2, 7.5, 5.2 and 5.4, respectively). The affinity of the compound for alpha 1, alpha 2, beta 1 and beta 2 adrenoceptors, and dopamine D2 receptors was at least 50-100 times lower than for 5-HT1A sites. The effects of SDZ 216-525, MDL 73005 and NAN 190 on 5-HT1 receptor-linked second messengers were characterised in the following tests: inhibition of forskolin-stimulated adenylate cyclase activity in calf hippocampus (5-HT1A), rat substantia nigra (5-HT1B) and calf substantia nigra (5-HT1D) and stimulation of inositol phosphate production in pig choroid plexus (5-HT1C). SDZ 216-525 potently antagonised the effects of 8-OH-DPAT (8-hydroxy-2-[N-dipropyl-amino]-tetralin) on 5-HT1A receptors (pKB = 10) and displayed no intrinsic activity in this test, whereas it behaved at best as a weak antagonist on the other receptor models (pKB values < 6.9).(ABSTRACT TRUNCATED AT 250 WORDS)
Collapse
MESH Headings
- 8-Hydroxy-2-(di-n-propylamino)tetralin/pharmacology
- Adenylyl Cyclases/metabolism
- Animals
- Behavior, Animal/drug effects
- Brain/drug effects
- Brain/metabolism
- Dioxins/metabolism
- Dioxins/pharmacology
- In Vitro Techniques
- Indoles/metabolism
- Indoles/pharmacology
- Male
- Phosphatidylinositols/metabolism
- Piperazines/metabolism
- Piperazines/pharmacology
- Radioligand Assay
- Rats
- Receptors, Adrenergic, alpha/drug effects
- Receptors, Adrenergic, alpha/metabolism
- Receptors, Adrenergic, beta/drug effects
- Receptors, Adrenergic, beta/metabolism
- Receptors, Dopamine D2/drug effects
- Receptors, Dopamine D2/metabolism
- Second Messenger Systems/drug effects
- Serotonin Antagonists/metabolism
- Serotonin Antagonists/pharmacology
- Spiro Compounds/metabolism
- Spiro Compounds/pharmacology
- Temperature
- Thiazoles/metabolism
- Thiazoles/pharmacology
Collapse
Affiliation(s)
- P Schoeffter
- Preclinical Research, Sandoz Pharma, Basel, Switzerland
| | | | | | | | | | | |
Collapse
|
15
|
Meller E, Chalfin M, Bohmaker K. Serotonin 5-HT1A receptor-mediated hypothermia in mice: absence of spare receptors and rapid induction of tolerance. Pharmacol Biochem Behav 1992; 43:405-11. [PMID: 1359573 DOI: 10.1016/0091-3057(92)90169-g] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
The mixed 5-hydroxytryptamine1A (5-HT1A) receptor agonist/antagonist 8-[2-[4-(2-methoxyphenyl)-1-piperazinyl]ethyl]-8-azaspirol-[4.5]- decane-7,9-dione (BMY 7378) (5 mg/kg) did not significantly depress body temperature, but pretreatment with BMY 7378 blocked hypothermia induced by the selective 5-HT1A agonist 8-hydroxy-2-(di-n-propylamino)tetralin (8-OH-DPAT). In contrast, another partial 5-HT1A agonist, pindolol (10 mg/kg), slightly but significantly depressed body temperature by itself but did not attenuate hypothermia elicited by 8-OH-DPAT. Attempts to identify the synaptic locus of the receptor were unsuccessful because depletion of central serotonin (5-HT) by treatment with para-chlorophenylalanine (PCPA; 3 x 150 mg/kg) did not alter the hypothermic response to 8-OH-DPAT. Partial, irreversible 5-HT1A receptor inactivation by N-ethoxycarbonyl-2-ethoxy-1,2-dihydroquinoline (EEDQ) (1 mg/kg) reduced the maximal hypothermic effect of 8-OH-DPAT (to 53% of control) without altering its ED50 (0.96 mg/kg). Analysis of the data indicated a linear relationship between 5-HT1A receptor occupancy and hypothermic response, that is, absence of receptor reserve. When groups of mice were treated with each of five different doses of 8-OH-DPAT (0.04, 0.16, 0.63, 2.5, and 10 mg/kg) 48 h apart, there was a significant reduction in hypothermic response after the second injection, but only at the three highest doses. The results demonstrate that 8-OH-DPAT-induced hypothermia in mice is mediated by a 5-HT1A receptor whose synaptic localization is uncertain but that has no receptor reserve. In addition, tolerance is observed after only a single agonist treatment.
Collapse
Affiliation(s)
- E Meller
- Millhauser Laboratories, Department of Psychiatry, New York University Medical Center, NY 10016
| | | | | |
Collapse
|
16
|
Buisson-Defferier S, Van den Buuse M. Cardiovascular effects of the 5-HT1A receptor ligand, MDL 73005EF, in conscious spontaneously hypertensive rats. Eur J Pharmacol 1992; 223:133-41. [PMID: 1362161 DOI: 10.1016/0014-2999(92)94831-f] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
The effects of pretreatment with the potent and selective 5-HT1A receptor ligand, MDL 73005EF, on the cardiovascular responses to administration of the 5-HT1A receptor agonists, 8-hydroxy-2-(di-n- propylamino)tetralin (8-OH-DPAT), flesinoxan and 5-methylurapidil were studied in conscious spontaneously hypertensive rats (SHR) and compared with those of putative 5-HT1A receptor antagonists. MDL 7300EF (0.1-3 mg/kg) induced a dose-dependent but transient decrease in mean arterial pressure (MAP). Pretreatment with doses of 1 or 3 mg/kg MDL 73005EF significantly inhibited the hypotensive and bradycardiac effects of 8-OH-DPAT (0.03-1 mg/kg). Pretreatment with 1 mg/kg MDL 73005EF similarly reduced the hypotensive actions of flesinoxan (0.3-1 mg/kg) and 5-methylurapidil (0.1 mg/kg). In contrast, MDL 73005EF did not significantly affect the decrease in blood pressure induced by administration of 0.01 mg/kg clonidine, 0.3 mg/kg hydralazine or 0.2 mg/kg nifedipine. The effect of 8-OH-DPAT (0.1 mg/kg) on MAP was also reduced by pretreatment with 1 mg/kg BMY 7378, buspirone or pindolol, but not NAN 190 or spiperone. BMY 7378, NAN 190, pindolol and spiperone induced a significant decrease in blood pressure. To rule out the possibility that the reduced baseline may have influenced responses to 8-OH-DPAT, we showed that pretreatment with the vasodilator, hydralazine (0.3 mg/kg), had no effect on the MAP response to 8-OH-DPAT although it significantly reduced MAP. We conclude that MDL 73005EF acts as a mixed agonist/antagonist at 5-HT1A receptors since it caused a decrease in blood pressure, but also reduced the cardiovascular responses to the 5-HT1A receptor agonists, 8-OH-DPAT, flesinoxan and 5-methylurapidil.
Collapse
|
17
|
Barrett JE, Gleeson S. Discriminative stimulus effects of 8-OH-DPAT in pigeons: antagonism studies with the putative 5-HT1A receptor antagonists BMY 7378 and NAN-190. Eur J Pharmacol 1992; 217:163-71. [PMID: 1425937 DOI: 10.1016/0014-2999(92)90841-q] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Pigeons were trained to discriminate 0.3 mg/kg of the 5-HT1A receptor agonist 8-hydroxy-2-(di-N-propylamino)tetralin (8-OH-DPAT) from saline. RU 24969 (5-methoxy-3-(1,2,3,6-tetrahydropyridin-4-yl)-1H-indole), at doses of 5.6-10 mg/kg, and eltoprazine (5.6 mg/kg), both mixed 5-HT1A/B agonists, substituted completely for 8-OH-DPAT, whereas 3.0-10 mg/kg of the 5-HT1B/C agonist TFMPP (1-(m-trifluromethylphenyl)piperazine) and 0.1-3.0 of the 5-HT3 antagonist MDL 72222 (3-tropanyl-3,5-dichlorobenzoate) yielded only saline-appropriate responses. Substitution for 8-OH-DPAT by eltoprazine and RU 24969, which does not occur in rats, provides in vivo support for the suggestion that the absence of a 5-HT1B receptor in the pigeon allows more complete expression of 5-HT1A-mediated effects. BMY 7378 (8-[2-[4-(2-methoxyphenyl)-1-piperazinyl]ethyl)]8-azaspirol-[4.5]- decane-7,9-dione) attenuated the 8-OH-DPAT stimulus at doses from 1.0 to 10 mg/kg but, when administered alone, also resulted in approximately 40% 8-OH-DPAT-appropriate responding at the highest dose. NAN-190 (1-(2-methoxyphenyl)-4-[4-(2-phthalamido)butyl)-piperazine (0.3-3.0 mg/kg) produced a dose-dependent and complete antagonism of the 8-OH-DPAT-discriminative stimulus; administered alone NAN-190 resulted only in saline-key responding. NAN-190 also reversed the rate-decreasing effects of higher doses of 8-OH-DPAT. The beta-adrenoceptor antagonist (+/-)-pindolol (5.6-17 mg/kg) antagonized the discriminative stimulus effects of lower 8-OH-DPAT doses but was unable to block the effects of higher doses of 8-OH-DPAT. Prazosin (1.0-10 mg/kg), which like NAN-190, is an alpha 1-antagonist, neither substituted for nor blocked the discriminative stimulus effects of 8-OH-DPAT. These results suggest that NAN-190 is an effective 5-HT1A receptor antagonist in this procedure with pigeons, with no indication of agonist actions, whereas BMY 7378 and pindolol are best characterized as partial 5-HT1A receptor agonists.
Collapse
Affiliation(s)
- J E Barrett
- Lederle Laboratories, American Cyanamid Company, Pearl River, NY 10965
| | | |
Collapse
|
18
|
Greuel JM, Glaser T. The putative 5-HT1A receptor antagonists NAN-190 and BMY 7378 are partial agonists in the rat dorsal raphe nucleus in vitro. Eur J Pharmacol 1992; 211:211-9. [PMID: 1535319 DOI: 10.1016/0014-2999(92)90531-8] [Citation(s) in RCA: 70] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
The present electrophysiological study examined the actions of the putative 5-HT1A receptor antagonists NAN-190 (1-(2-methoxyphenyl)-4-[4-(2-phthalimido)butyl]piperazine) and BMY 7378 (8-[2-[4-(2-methoxyphenyl)-1-piperazinyl]ethyl]-8-azaspiro[4,5]- decane-7,9-dione dihydrochloride) in the rat dorsal raphe nucleus in vitro. There was no major difference between the effects of the two drugs on any measure investigated. Both compounds reduced neuronal activity in a concentration-dependent manner, with BMY 7378 being slightly more potent than NAN-190. The threshold concentrations eliciting inhibitory effects were 1 nM for BMY 7378 and 3 nM for NAN-190. Complete inhibition occurred at concentrations close to 30 nM. The effects of the 5-HT1A receptor agonist 8-OH-DPAT (8-hydroxy-2-(di-n-propylamino)tetralin) could be antagonized when concentrations of NAN-190 or BMY 7378 were used that were too low to produce a marked inhibition. At concentrations close to threshold both compounds potentiated the inhibitory effects of 3 nM 8-OH-DPAT. The suppression of neuronal firing induced by NAN-190 and BMY 7378 could be completely antagonized with propranolol, indicating that the inhibitory actions of both drugs were not primarily due to alpha 1-adrenoceptor antagonism. By applying theorems of receptor theory the intrinsic activities for both NAN-190 and BMY 7378 were calculated to be in the range of 0.1-0.3. Thus, NAN-190 and BMY 7378 are partial agonists in the rat dorsal raphe nucleus.(ABSTRACT TRUNCATED AT 250 WORDS)
Collapse
Affiliation(s)
- J M Greuel
- Institute for Neurobiology, Troponwerke GmbH & Co. KG, F.R.G
| | | |
Collapse
|