1
|
Durant CF, Paterson LM, Turton S, Wilson SJ, Myers JFM, Muthukumaraswamy S, Venkataraman A, Mick I, Paterson S, Jones T, Nahar LK, Cordero RE, Nutt DJ, Lingford-Hughes A. Using Baclofen to Explore GABA-B Receptor Function in Alcohol Dependence: Insights From Pharmacokinetic and Pharmacodynamic Measures. Front Psychiatry 2018; 9:664. [PMID: 30618857 PMCID: PMC6302106 DOI: 10.3389/fpsyt.2018.00664] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/21/2018] [Accepted: 11/19/2018] [Indexed: 12/20/2022] Open
Abstract
Background: The role of GABA-B neurotransmission in addiction has recently received increased attention, with clinical trials indicating that baclofen, a GABA-B receptor agonist, may reduce alcohol consumption, craving and promote abstinence. However, the optimal dose to treat alcohol dependence is unclear with patients requesting and tolerating much higher doses of baclofen, compared with other clinical uses. We assessed the pharmacokinetics and pharmacodynamics (PK/PD) of baclofen to provide insight into GABA-B sensitivity in this patient group, relative to controls. Methods: Male healthy volunteers (controls, n = 12) and abstinent alcohol dependent individuals (AD, n = 8) received single oral doses of baclofen or placebo in a 3-way crossover design. Controls received placebo/10 mg/60 mg baclofen in a randomized, double-blind design, AD received placebo/60 mg/90 mg baclofen in a single-blind design. PK/PD measures were recorded at baseline and multiple time-points up to 6 h post-dosing, including plasma baclofen, plasma growth hormone (GH), Subjective High Assessment Scale (SHAS) and biphasic alcohol effects scale (BAES). Repeated measures ANOVA analysis explored "change from baseline" dose, time, group, and interaction effects, t-tests compared peak effects. Results: Dose-dependent effects of baclofen on PK and PD measures were observed in both control and AD groups. Whilst there were no significant group differences in any baclofen PK parameters (t 1/2, t max , C max , AUC), marked differences in PD effects were clearly evident. In controls, 60 mg baclofen significantly increased total SHAS and BAES scores, and significantly increased plasma GH levels compared with placebo, with peak effects at 60-120 min, in line with its PK profile. In AD, 60 mg baclofen had limited effects on these parameters; SHAS scores, BAES scores and plasma GH levels were significantly blunted compared with controls (significant group*time interactions P = 0.0014, 0.0015 and P < 0.0001, respectively). Conclusions: Our study shows blunted sensitivity to baclofen in AD relative to controls, with no difference in PK suggesting a lower GABA-B receptor sensitivity. This may explain why higher baclofen doses are requested and tolerated in the treatment of alcohol dependence. Our data has implications for choice of dose in future clinical trials in AD and possibly other substances of dependence.
Collapse
Affiliation(s)
- Claire F Durant
- Neuropsychopharmacology Unit, Division of Brain Sciences, Department of Medicine, Centre for Psychiatry, Imperial College London, London, United Kingdom
| | - Louise M Paterson
- Neuropsychopharmacology Unit, Division of Brain Sciences, Department of Medicine, Centre for Psychiatry, Imperial College London, London, United Kingdom
| | - Sam Turton
- Neuropsychopharmacology Unit, Division of Brain Sciences, Department of Medicine, Centre for Psychiatry, Imperial College London, London, United Kingdom
| | - Susan J Wilson
- Neuropsychopharmacology Unit, Division of Brain Sciences, Department of Medicine, Centre for Psychiatry, Imperial College London, London, United Kingdom
| | - James F M Myers
- Neuropsychopharmacology Unit, Division of Brain Sciences, Department of Medicine, Centre for Psychiatry, Imperial College London, London, United Kingdom
| | | | - Ashwin Venkataraman
- Neuropsychopharmacology Unit, Division of Brain Sciences, Department of Medicine, Centre for Psychiatry, Imperial College London, London, United Kingdom
| | - Inge Mick
- Neuropsychopharmacology Unit, Division of Brain Sciences, Department of Medicine, Centre for Psychiatry, Imperial College London, London, United Kingdom
| | - Susan Paterson
- Centre for Brain Science, University of Auckland, Auckland, New Zealand
| | - Tessa Jones
- Neuropsychopharmacology Unit, Division of Brain Sciences, Department of Medicine, Centre for Psychiatry, Imperial College London, London, United Kingdom
| | - Limon K Nahar
- Centre for Brain Science, University of Auckland, Auckland, New Zealand
| | - Rosa E Cordero
- Centre for Brain Science, University of Auckland, Auckland, New Zealand
| | - David J Nutt
- Neuropsychopharmacology Unit, Division of Brain Sciences, Department of Medicine, Centre for Psychiatry, Imperial College London, London, United Kingdom
| | - Anne Lingford-Hughes
- Neuropsychopharmacology Unit, Division of Brain Sciences, Department of Medicine, Centre for Psychiatry, Imperial College London, London, United Kingdom
| |
Collapse
|
2
|
Bauman WA, Kirshblum SC, Morrison NG, Cirnigliaro CM, Zhang RL, Spungen AM. Effect of low-dose baclofen administration on plasma insulin-like growth factor-I in persons with spinal cord injury. J Clin Pharmacol 2006; 46:476-82. [PMID: 16554457 DOI: 10.1177/0091270006286641] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Patients with chronic spinal cord injury (SCI), a condition associated with reduced physical function, have been reported to have lower plasma insulin-like growth factor-I (IGF-I) levels than able-bodied persons. We evaluated the potential for daily low-dose baclofen administered over several weeks to increase plasma IGF-I levels. Ten healthy male outpatients with chronic SCI were studied prospectively. Patients received escalating doses of baclofen for 4 weeks at each dose level (5, 10, and 20 mg/d). At each dose of baclofen, an increase in the plasma IGF-I was noted; significant increases in plasma IGF-I occurred at 2 weeks after administration of drug at doses of 10 and 20 mg/d, with a subsequent rise to peak levels on baclofen 20 mg/d [baseline, 205+/-74; peak, 218+/-76 (not significant), 239+/-83 (P<.05), 263+/-87 microg/L (P<.05), at baclofen 5, 10, and 20 mg/d, respectively]. In conclusion, low-dose baclofen administration for 4 weeks stimulated the growth hormone-IGF-I axis in persons with SCI, with the potential for beneficial effects on body composition.
Collapse
Affiliation(s)
- William A Bauman
- Veterans Affairs Rehabilitation Research and Development Center of Excellence, Veterans Affairs Medical Center, 130 West Kingsbridge Road, Bronx, NY 10468, and the Department of Medicine, Mount Sinai School of Medicine, New York, NY, USA
| | | | | | | | | | | |
Collapse
|
4
|
Rigamonti AE, Müller EE. Gamma-hydroxybutyric acid and growth hormone secretion studies in rats and dogs. Alcohol 2000; 20:293-304. [PMID: 10869872 DOI: 10.1016/s0741-8329(99)00094-4] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Gamma-hydroxybutyric acid, a gamma-aminobutyric acid metabolite, and baclofen, a gamma-aminobutyric acid B agonist, are endowed with a small growth hormone-releasing activity in human beings. In this study, we have investigated the reciprocal interactions of gamma-hydroxybutyric acid and the gamma-aminobutyric acid B system by evaluating the growth hormone-releasing activity of the two compounds and their respective antagonists in in vivo and in vitro experiments performed in rats and dogs. In in vivo experiments, neither gamma-hydroxybutyric acid (25, 100, 150, and 300 mg/kg, SC) nor baclofen (0.25, 1, 2, 4, and 8 mg/kg, SC) significantly modified growth hormone secretion in 9-day-old rat pups. Similarly, no growth hormone and prolactin release was observed in adult anesthetized rats after administration of gamma-hydroxybutyric acid (100 mg/kg, IP) or baclofen (10 mg/kg IP). Equally ineffective on the somatotropic response was the administration of gamma-hydroxybutyric acid (200 mg/kg, IP) alone or associated with its specific receptor antagonist NCS-382 (150 mg/kg, IP) given to adult anesthetized rats. In addition, a toxicological dose of gamma-hydroxybutyric acid (1500 mg/kg, IP) did not alter baseline growth hormone levels in adult conscious rats. gamma-Hydroxybutyric acid (50 mg/kg, IP) given for 10 days to adult conscious rats did not alter the growth hormone response to the same gamma-hydroxybutyric acid dose given acutely. In conscious dogs, gamma-hydroxybutyric acid (20 and 50 mg/kg, IV) and baclofen (0.15, 0.30 mg/kg, IV) also were ineffective in stimulating growth hormone secretion. In this species, growth hormone response to hexarelin (31.25 microg/kg, IV), a potent growth hormone-releasing peptide, was not modified by coadministration of gamma-hydroxybutyric acid (50 mg/kg, IV). In in vitro experiments, increasing doses of gamma-hydroxybutyric acid (10(-7), 10(-5), and 10(-3) M) did not alter growth hormone concentrations in media of rat pituitary cell cultures. In contrast, growth hormone-releasing hormone (10(-7) M) induced a significant growth hormone release into the media. In conclusion (1) gamma-hydroxybutyric acid is not an effective growth hormone secretagogue; (2) the reciprocal functional interactions between gamma-hydroxybutyric acid and the gamma-aminobutyric acid B system could not be investigated, due to the ineffectiveness of gamma-hydroxybutyric acid and baclofen to stimulate growth hormone release; and (3) short-term administration of gamma-hydroxybutyric acid does not induce adverse effects amenable to activation of the somatotropic function.
Collapse
Affiliation(s)
- A E Rigamonti
- Department of Pharmacology, Chemotherapy, and Toxicology, University of Milan, via Vanvitelli 32, 20129, Milan, Italy.
| | | |
Collapse
|
5
|
Abstract
The secretion of growth hormone (GH) is regulated through a complex neuroendocrine control system, especially by the functional interplay of two hypothalamic hypophysiotropic hormones, GH-releasing hormone (GHRH) and somatostatin (SS), exerting stimulatory and inhibitory influences, respectively, on the somatotrope. The two hypothalamic neurohormones are subject to modulation by a host of neurotransmitters, especially the noradrenergic and cholinergic ones and other hypothalamic neuropeptides, and are the final mediators of metabolic, endocrine, neural, and immune influences for the secretion of GH. Since the identification of the GHRH peptide, recombinant DNA procedures have been used to characterize the corresponding cDNA and to clone GHRH receptor isoforms in rodent and human pituitaries. Parallel to research into the effects of SS and its analogs on endocrine and exocrine secretions, investigations into their mechanism of action have led to the discovery of five separate SS receptor genes encoding a family of G protein-coupled SS receptors, which are widely expressed in the pituitary, brain, and the periphery, and to the synthesis of analogs with subtype specificity. Better understanding of the function of GHRH, SS, and their receptors and, hence, of neural regulation of GH secretion in health and disease has been achieved with the discovery of a new class of fairly specific, orally active, small peptides and their congeners, the GH-releasing peptides, acting on specific, ubiquitous seven-transmembrane domain receptors, whose natural ligands are not yet known.
Collapse
Affiliation(s)
- E E Müller
- Department of Pharmacology, Chemotherapy, and Toxicology, University of Milan, Milan, Italy
| | | | | |
Collapse
|
6
|
Shiah IS, Robertson HA, Lam RW, Yatham LN, Tam EM, Zis AP. Growth hormone response to baclofen in patients with seasonal affective disorder: effects of light therapy. Psychoneuroendocrinology 1999; 24:143-53. [PMID: 10101723 DOI: 10.1016/s0306-4530(98)00066-3] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/16/2022]
Abstract
There is evidence for gamma-aminobutyric acid (GABA) dysfunction in the pathophysiology and treatment response of patients with major depression, but this has not been studied in seasonal affective disorder (SAD). Growth hormone (GH) response to a challenge with a GABAB receptor agonist, baclofen, is considered an in vivo index of hypothalamic GABAB receptor function in humans. To explore the role of GABAB receptor function in SAD, we compared the GH response to baclofen challenge in 15 patients with SAD and 20 matched healthy controls. Of the 15 patients with SAD, 14 had repeat baclofen challenge following 2-week treatment with light therapy. The results showed that baclofen administration led to a significant increase in GH release both in patients with SAD and normal controls. There was no significant difference in the GH response to baclofen between the two groups. Furthermore, 2-week treatment with light therapy did not significantly alter the baclofen-induced GH response in patients with SAD, in spite of a clear therapeutic effect. The results of this study suggest that hypothalamic GABAB receptor function, as measured by baclofen induced GH release, is not altered in patients with SAD or by light therapy.
Collapse
Affiliation(s)
- I S Shiah
- Department of Psychiatry, University of British Columbia, Vancouver, Canada
| | | | | | | | | | | |
Collapse
|
7
|
Davis LL, Trivedi M, Choate A, Kramer GL, Petty F. Growth hormone response to the GABAB agonist baclofen in major depressive disorder. Psychoneuroendocrinology 1997; 22:129-40. [PMID: 9203224 DOI: 10.1016/s0306-4530(96)00048-0] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Growth hormone (GH) response to the gamma-aminobutyric acid B receptor agonist, baclofen, was measured in 16 male patients with major depressive disorder and in 16 age-matched healthy male controls. No significant differences were found in the GH response to baclofen between the depressed patients and controls. On repeat testing, the GH response to baclofen showed significant retest reliability in both groups. There was no significant correlation between serum baclofen levels and the GH response to baclofen. Age significantly correlated with GH response, with older subjects having lower GH response to baclofen. These data do not suggest that a blunted GH response to baclofen. represents a specific neuroendocrine feature of major depression.
Collapse
Affiliation(s)
- L L Davis
- Veterans Affairs Medical Center, Dallas, TX 75216, USA.
| | | | | | | | | |
Collapse
|