Acta Psychiatr Scand. 1989 Feb;79(2):129-35.
Explorative single-blind study on the sedative and hypnotic effects of buspirone in anxiety patients.

De Roeck J, Cluydts R, Schotte C, Rouckhout D, Cosyns P.

Department of Psychiatry, University Hospital Antwerp, Edegem, Belgium.

In this single-blind study the sedative and hypnotic properties of buspirone, a nonbenzodiazepine anxiolytic, were investigated in 8 anxious outpatients. Polysomnographic recordings were gathered during baseline, at the start of active medication, after 3 weeks of treatment and one night after discontinuing treatment. Daytime alertness was measured using the Multiple Sleep Latency Test and performance tests. The effects of buspirone on sleep structure were minimal and of no clinical consequence. Subjectively, the patients reported improved sleep quality. There were no effects on daytime alertness at the beginning, after 3 weeks or at sudden discontinuation of the medication. It is concluded that buspirone does not have a sedative or hypnotic effect in anxiety patients.

http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=2923006&dopt=Abstract buspirone Buspar




Am Rev Respir Dis. 1989 Apr;139(4):946-50.
Buspirone, an anxiolytic drug that stimulates respiration.

Garner SJ, Eldridge FL, Wagner PG, Dowell RT.

Department of Medicine, University of North Carolina, Chapel Hill 27599.

The recently released drug buspirone is an anxiolytic agent that appears not to have the sedating effects of barbiturates and benzodiazepines, both known to have respiratory depressant effects. Because of its increasing clinical use, we desired to study the effects of buspirone on respiratory control. We therefore determined central neural respiratory responses, measured from phrenic nerve activity, after intravenous administration in paralyzed, vagotomized, and glomectomized cats whose end-tidal PCO2 and body temperature were kept constant. The responses were compared to the effects of the sedating tranquilizer diazepam. Buspirone had a dose-dependent stimulatory effect on respiratory output primarily through an increase of tidal activity but with an increase of frequency in some animals. Associated with this was a shift of the apneic threshold to a lower level of PCO2 without a change of slope or shape of the CO2 response curve. In contrast, diazepam led to a depression of respiration and a shift of the apneic threshold to a higher PCO2. The findings indicate that buspirone does not have the typical neural respiratory depressant actions of diazepam but instead stimulates respiration. Although the findings will need to be shown to apply to human beings, they suggest that buspirone may be a useful drug to treat anxiety in patients without causing undesirable respiratory depression.

http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=2930071&dopt=Abstract buspirone Buspar




Pharmacol Biochem Behav. 1986 Jun;24(6):1513-9.
Differential effects of 5-hydroxytryptamine1a selective drugs on the 5-HT behavioral syndrome.

Smith LM, Peroutka SJ.

The effects of 8-hydroxy-2-(di-n-propyl-amino) tetralin (8-OH-DPAT), 5-methoxy-N,N-dimethyltryptamine (5-MeODMT), buspirone and isapirone were examined at 5-hydroxytryptamine1A (5-HT1A) binding sites and on the 5-HT behavioral syndrome in the rat. 8-OH-DPAT, 5-MeODMT, buspirone and isapirone are all potent inhibitors of 3H-8-OH-DPAT binding to rat brain membranes (Ki values = 1.9-13 nM). However, these drugs have differential effects on the 5-HT behavioral syndrome. 8-OH-DPAT, 5-MeODMT and buspirone induce hindlimb abduction, flattened body posture and Straub tail. Isapirone induces only a slight flattening of body posture. By contrast, 8-OH-DPAT and 5-MeODMT, but not buspirone and isapirone, and isapirone, also induce forepaw treading, head-weaving and tremor. However, both buspirone and isapirone antagonize the induction of these three behaviors by 8-OH-DPAT or 5-MeODMT. These data show that 8-OH-DPAT and 5-MeODMT are "full agonists" in relation to six components of the 5-HT behavioral syndrome. Buspirone and isapirone, on the other hand, act as "antagonists" in relation to forepaw treading, head-weaving and tremor. Therefore, these data suggest that specific components of the 5-HT behavioral syndrome are mediated by 5-HT1A receptors.

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Life Sci. 1988;42(10):1045-8.
Pharmacokinetics of buspirone as determined by ex vivo (3H)-DPAT binding.

Sethy VH, Francis JW.

CNS Diseases Research, Upjohn Company, Kalamazoo, MI 49001.

Ex vivo (3H)-8-hydroxy-2-(di-n-propylamino)-tetraline ((3H)-DPAT) binding to the hippocampus has been utilized to determine the pharmacokinetic parameters of buspirone after i.v. (30 mumol/kg) and oral (100 mumol/kg) administration of this drug to rats. Intravenous buspirone rapidly penetrated the brain as demonstrated by a maximum inhibition of (3H)-DPAT binding at 1 min. Elimination of drug from the brain was biphasic, with a first component half-life of 24.8 min and a second component half-life of 96 min. Oral buspirone at 3 times the i.v. dose produced less than one-third the maximum inhibition of (3H)-DPAT binding compared to that observed with i.v. buspirone. The pharmacokinetic parameters of buspirone observed in the present study are in agreement with those reported previously. Thus, the ex vivo binding assay could be utilized to determine the bioavailability of the drug to the brain, and its duration of action.

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Biull Eksp Biol Med. 1986 Sep;102(9):292-4.
[Effect of buspirone and diazepam on cGMP level in the rat cerebellum]

[Article in Russian]

Korneev AIa, Chan TB, Faktor MI.

Diazepam at a dose of 5 and 10 mg/kg significantly decreases (by 50 and 60%, respectively) cGMP content 30 min following intraperitoneal injection to rats. Buspirone, at a dose of 2.5-25 mg/kg produced a nonsignificant (up to 18%) and at a dose of 50 mg/kg a statistically significant (p less than 0.05) 30% decrease in cerebellum cGMP content. Taking into account the identical anxiolytic effects of diazepam and buspirone, it is suggested that pharmacological effects of buspirone are not linked to the activation of GABA-ergic system.

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J Pharmacol Exp Ther. 1987 Jun;241(3):771-8.
Tissue-dependent alpha adrenoceptor activity of buspirone and related compounds.

Rimele TJ, Henry DE, Lee DK, Geiger G, Heaslip RJ, Grimes D.

The present organ chamber and receptor binding studies were designed to evaluate the alpha adrenoceptor subtype (alpha-1 vs. alpha-2) and tissue selectivity of buspirone and the related compounds, gepirone, isapirone and 1-(2-pyrimidinyl)-piperazine (a metabolite of buspirone). Buspirone, gepirone and isapirone were found to possess weak alpha-1 adrenoceptor affinity (relative to prazosin) but significant and selective alpha-1 adrenoceptor intrinsic efficacy (relative to norepinephrine, phenylephrine and ST-587), which was expressed in a tissue- and species-dependent manner. The rank order for alpha-1 adrenoceptor affinity (isapirone greater than buspirone approximately equal to gepirone) was different from the rank order for alpha-1 adrenoceptor intrinsic efficacy (buspirone greater than gepirone greater than isapirone). The tissues that were the most responsive to norepinephrine and ST-587 (i.e., rat and rabbit aorta) were the same tissues in which the intrinsic efficacy of buspirone was expressed. In contrast, 1-(2-pyrimidinyl)-piperazine was inactive at alpha-1 adrenoceptors. Although no alpha-2 adrenoceptor intrinsic efficacy was observed for any of the compounds, isapirone and 1-(2-pyrimidinyl)-piperazine displayed weak alpha-2 adrenoceptor affinity (relative to rauwolscine). Recent studies have shown buspirone to have an effect on central and peripheral monoaminergic mechanisms. The demonstration in the present study that buspirone and related compounds display significant alpha adrenoceptor activity suggests that alpha adrenoceptor involvement should be considered as a potential contributing factor in the central nervous system and/or peripheral activity of this class of compounds.

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J Chromatogr. 1988 Jul 15;428(2):265-74.
Simultaneous quantitation of buspirone and 1-(2-pyrimidinyl)piperazine in human plasma and urine by capillary gas chromatography-mass spectrometry.

Sciacca MA, Duncan GF, Shea JP, Faulkner HC 3rd, Farmen RH, Pittman KA.

Department of Metabolism and Pharmackinetics, Bristol-Myers Company, Syracuse, NY 13221.

Buspirone and a buspirone metabolite, 1-(2-pyrimidinyl)piperazine (1-PP), are extracted from matrix using C18 extraction columns. The metabolite and its internal standard (d4-1-PP) are derivatized with pentafluorobenzoyl chloride to the corresponding amides. The 1-PP derivatives, buspirone and the buspirone internal standard (5-fluorobuspirone) are co-chromatographed. Chromatography and detection are performed using capillary gas chromatography with a fused-silica column and selected-ion monitoring-mass spectrometry. Linear range of the standard curves in plasma is 0.1-14 ng/ml for buspirone and 0.2-25 ng/ml for 1-PP with lower limits of quantitation of 0.1 and 0.2 ng/ml, respectively. In urine the linear range of the standard curves is 0.2-14 ng/ml for buspirone and 8-500 ng/ml for 1-PP with lower limits of quantitation of 0.2 and 8.0 ng/ml, respectively. Intra-assay accuracies were within 14% for buspirone and 1-PP in plasma and urine. Intra-assay precision was within 12% for both compounds in both matrices.

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Neuropharmacology. 1988 Aug;27(8):823-30.
A comparison of the effects of buspirone and diazepam on plasma corticosterone levels in rat.

Matheson GK, Gage D, White G, Dixon V, Gipson D.

Neurobiology Laboratory, Indiana University School of Medicine, Evansville 47722.

The effect of the anxiolytic agents, buspirone and diazepam, on the hypothalamic-pituitary-adrenal axis (HPAA), indicated by changes in the concentration of corticosterone (CS) in plasma, were studied 1/2, 1, 2, 4, 6, 8 and 24 hr after administration of the drug (i.p.). Samples of plasma were collected in the mid-morning (0930-1130 hr) when activity in the hypothalamic-pituitary-adrenal axis in the rat and control levels of corticosterone were low and were repeated in the afternoon (1400-1600 hr) when activity in the hypothalamic-pituitary-arenal axis and levels of corticosterone were higher. At small doses (1 mg/kg) buspirone had a greater facilitating effect on the hypothalamic-pituitary-adrenal axis than did diazepam. In addition, buspirone had a greater maximum facilitatory effect (477%) on levels of corticosterone than diazepam (345%). However, buspirone (ED50 = 8.6 mumol/kg) and diazepam (ED50 = 8.7 mumol/kg) were equipotent. Administration of 1 mg/kg of buspirone in the morning increased the combined 1/2 and 1 hr circulating levels of corticosterone 75% above control levels. Diazepam, at 1 mg/kg, did not produce any significant changes in levels of corticosterone. Large doses (10 mg/kg) of buspirone increased morning levels of corticosterone by 328% and diazepam increased levels of corticosterone by 265%. During the afternoon small doses of buspirone or diazepam did not significantly alter levels of corticosterone.(ABSTRACT TRUNCATED AT 250 WORDS)

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