Interpreting the Relationship Among Itch, Sleep, and Work Productivity in Patients with Moderate-to-Severe Atopic Dermatitis: A Post Hoc Analysis of JADE MONO-2.

BACKGROUND: Abrocitinib, an oral, once-daily Janus kinase 1-selective inhibitor, improved itch severity, sleep, and work productivity versus placebo in patients with moderate-to-severe atopic dermatitis. OBJECTIVE: The aim of this study was to investigate relationships among itch, sleep, and work productivity in the phase III JADE MONO-2 clinical trial. METHODS: A repeated-measures longitudinal model was used to examine relationships between itch (using the Peak Pruritus Numerical Rating Scale [PP-NRS] or Nighttime Itch Scale [NTIS]) and sleep disturbance/loss (using the Patient-Oriented Eczema Measure sleep item and SCORing AD Sleep Loss Visual Analog Scale) and, separately, between itch and work productivity (using the Work Productivity and Activity Impairment-Atopic Dermatitis Version 2.0 questionnaire). Mediation modelling was used to investigate the effect of treatment (abrocitinib vs placebo) on work impairment via improvements in itch and sleep. RESULTS: The relationships between itch/sleep and itch/work productivity were approximately linear. PP-NRS scores of 0, 4-6, and 10 were associated with 0 days, 3-4 days, and 7 days per week of disturbed sleep, respectively. PP-NRS or NTIS scores of 0-1, 4-5, and 10 were associated with 0-10%, 20-30%, and >50% overall work impairment, respectively. Seventy-five percent of the effect of abrocitinib on reducing work impairment was indirectly mediated by improvement in itch, followed by sleep. CONCLUSION: These results quantitatively demonstrate that reducing itch severity is associated with improvements in sleep and work productivity. Empirical evidence for the mechanism of action of abrocitinib showed that itch severity is improved, which reduces sleep loss/sleep disruption and, in turn, improves work productivity. CLINICAL TRIAL REGISTRATION: NCT03575871.

Atopic dermatitis (AD), also called atopic eczema, is a common skin disease that is associated with itch and reduced quality of life. Abrocitinib, a recently approved medicine for AD, was shown in clinical trials to improve itch, which is considered the most bothersome symptom to people with AD. Abrocitinib also improved sleep outcomes and work productivity in people with moderate or severe AD. It is unknown if improvement in itch can lead to improvement in sleep and work productivity. We analyzed data from the JADE MONO-2 study, which included 391 people who received treatment with abrocitinib or placebo for 12 weeks. We used mathematical modelling to study relationships between itch and sleep or work productivity. We also wanted to study if the improvements in itch and sleep with abrocitinib treatment had an impact on work productivity. We found that a relationship existed between itch, sleep disturbance, and work impairment; as itch improved, so too did sleep disturbance and work impairment. When people were treated with abrocitinib, they experienced relief from itch, which improved sleep, which in turn reduced work productivity loss. Larger and longer studies are needed to confirm these results. This analysis further informs the expectations of patients with moderate or severe AD as it relates to progression of symptom relief after treatment with abrocitinib.

Maintenance of Remission With Tofacitinib Therapy in Patients With Ulcerative Colitis.

BACKGROUND & AIMS: Tofacitinib is an oral, small molecule Janus kinase inhibitor for the treatment of ulcerative colitis (UC). The efficacy and safety of tofacitinib in patients with moderate to severe UC, up to 1 year, have been reported. We investigated maintenance of efficacy in patients in remission after 52 weeks of maintenance treatment in the pivotal phase 3 study (OCTAVE Sustain); these patients received open-label, long-term treatment with tofacitinib 5 mg twice daily. METHODS: Patients with moderate to severe UC who completed a 52-week, phase 3 maintenance study (OCTAVE Sustain) were eligible to enroll into the ongoing, phase 3, multicenter, open-label, long-term extension (OCTAVE Open). We analyzed data from 142 patients who were in remission following tofacitinib treatment in OCTAVE Sustain who received tofacitinib 5 mg twice daily during OCTAVE Open. We assessed efficacy (including remission [based on total Mayo score], endoscopic improvement, clinical response, and partial Mayo score up to month 36 of OCTAVE Open) and safety data. RESULTS: After 12 months of tofacitinib 5 mg twice daily in OCTAVE Open, 68.3% of patients were in remission, 73.9% had endoscopic improvement, and 77.5% had a clinical response. At month 36, 50.4%, of the patients were in remission, 55.3% had endoscopic improvement, and 56.0% had a clinical response. The safety profile of tofacitinib 5 mg twice daily revealed no new safety risks associated with long-term exposure up to 36 months. CONCLUSIONS: Efficacy endpoints were maintained for up to 36 months, regardless of prior tofacitinib dose, including patients who reduced from tofacitinib 10 mg to 5 mg twice daily upon OCTAVE Open entry. No new safety risks were identified. ClinicalTrials.gov: OCTAVE Sustain (NCT01458574); OCTAVE Open (NCT01470612).

Integrated Safety Analysis of Abrocitinib for the Treatment of Moderate-to-Severe Atopic Dermatitis From the Phase II and Phase III Clinical Trial Program.

BACKGROUND: Pivotal phase III studies demonstrated that abrocitinib, an oral, once-daily, JAK1-selective inhibitor, is effective treatment for moderate-to-severe atopic dermatitis (AD) as monotherapy and in combination with topical therapy. OBJECTIVE: The aim of this study was to evaluate the long-term safety of abrocitinib 200 mg and 100 mg in an integrated analysis of a phase IIb study, four phase III studies, and one long-term extension study. METHODS: Two cohorts were analyzed: a placebo-controlled cohort from 12- to 16-week studies and an all-abrocitinib cohort including patients who received one or more abrocitinib doses. Adverse events (AEs) of interest and laboratory data are reported. RESULTS: Total exposure in the all-abrocitinib cohort (n = 2856) was 1614 patient-years (PY); exposure was ≥ 24 weeks in 1248 patients and ≥ 48 weeks in 606 (maximum 108 weeks). In the placebo-controlled cohort (n = 1540), dose-related AEs (200 mg, 100 mg, placebo) were nausea (14.6%, 6.1%, 2.0%), headache (7.8%, 5.9%, 3.5%), and acne (4.7%, 1.6%, 0%). Platelet count was reduced transiently in a dose-dependent manner; 2/2718 patients (200-mg group) had confirmed platelet counts of < 50 × 103/mm3 at week 4. Incidence rates (IRs) were 2.33/100PY and 2.65/100 PY for serious infection, 4.34/100PY and 2.04/100PY for herpes zoster, and 11.83/100PY and 8.73/100PY for herpes simplex in the 200-mg and 100-mg groups, respectively. IRs for nonmelanoma skin cancer, other malignancies, and major adverse cardiovascular events were < 0.5/100PY for both doses. Five venous thromboembolism events occurred (IR 0.30/100PY), all in the 200-mg group. There were three deaths due to gastric carcinoma (diagnosed at day 43), sudden death, and COVID-19. CONCLUSION: Abrocitinib, with proper patient and dose selection, has a manageable tolerability and longer-term safety profile appropriate for long-term use in patients with moderate-to-severe AD. TRIAL REGISTRIES: ClinicalTrials.gov: NCT02780167, NCT03349060, NCT03575871, NCT03720470, NCT03627767, NCT03422822.

Tofacitinib for the Treatment of Ulcerative Colitis: Analysis of Infection Rates from the Ulcerative Colitis Clinical Programme.

BACKGROUND AND AIMS: Tofacitinib is an oral, small molecule JAK inhibitor for the treatment of ulcerative colitis. We report integrated analyses of infections in the Phase [P]2 and P3 OCTAVE programmes. METHODS: Three cohorts were analysed: Induction [P2/3 induction studies]; Maintenance [P3 maintenance study]; and Overall [all tofacitinib-treated patients in induction, maintenance, or ongoing, open-label, long-term extension studies; as of May 2019]. Proportions and incidence rates [IRs; unique patients with events/100 patient-years] of serious infections [SIs], herpes zoster [HZ] [non-serious and serious], and opportunistic infections [OIs] are reported [censored at time of event]. RESULTS: In the Induction Cohort [N = 1220], no patients receiving placebo and eight [0.9%] receiving tofacitinib 10 mg twice daily [BID] developed SIs. Maintenance Cohort [N = 592] SI IRs (95% confidence interval [CI]) were 1.94 [0.23-7.00] for placebo and 1.35 [0.16-4.87] and 0.64 [0.02-3.54] for tofacitinib 5 and 10 mg BID, respectively; HZ IRs were 0.97 [0.02-5.42], 2.05 [0.42-6.00], and 6.64 [3.19-12.22], respectively. In the Overall Cohort [N = 1157; 82.9% predominantly received tofacitinib 10 mg BID], SI, HZ, and non-HZ OI IRs were 1.70 [1.24-2.27], 3.48 [2.79-4.30], and 0.15 [0.04-0.38], respectively. No SIs resulted in death. CONCLUSIONS: During induction, SIs were more frequent with tofacitinib versus placebo. SIs were generally infrequent in the Maintenance and Overall Cohorts, with rates comparable between treatment groups. Maintenance Cohort HZ IR was numerically higher with tofacitinib 10 mg BID versus 5 mg BID. Overall Cohort HZ IRs remained stable over time. Non-HZ OIs and viral infections were rare.

Tofacitinib in Patients with Ulcerative Colitis: Inflammatory Bowel Disease Questionnaire Items in Phase 3 Randomized Controlled Induction Studies.

BACKGROUND: Tofacitinib is an oral, small molecule Janus kinase inhibitor for the treatment of ulcerative colitis (UC). We examined the effect of tofacitinib induction treatment on Inflammatory Bowel Disease Questionnaire (IBDQ) items in adults with moderate to severe UC. METHODS: Data were pooled from the randomized, 8­week, double-blind, phase 3 OCTAVE Induction 1 and 2 studies. The IBDQ was self-administered by patients at baseline, week 4, and week 8, with higher scores indicating better health-related quality of life (HRQoL). Change from baseline in IBDQ items was analyzed for 10 mg of tofacitinib twice daily (BID) vs placebo using a linear mixed-effects model, with no multiplicity adjustment performed. Effect sizes were calculated. Subgroup analyses by tumor necrosis factor inhibitor (TNFi) experience were performed. RESULTS: Significant improvements (nominal P < 0.05) were observed in all IBDQ items with 10 mg of tofacitinib BID vs placebo at weeks 4 and 8. For the overall population, the largest treatment differences across all items were reported for "bowel movements been loose" at weeks 4 and 8, and "problem with rectal bleeding" at week 8 (mean treatment differences all 1.1; both in bowel symptoms domain). These items also showed the largest effect sizes. Treatment benefits were generally slightly numerically higher in TNFi-experienced vs TNFi-naïve patients. CONCLUSIONS: Tofacitinib induction therapy improved all IBDQ items vs placebo in patients with UC, reflecting improvements in HRQoL, with greatest benefits reported in bowel symptoms domain items (Funded by Pfizer Inc; OCTAVE Induction 1 and OCTAVE Induction 2; ClinicalTrials.gov, NCT01465763 and NCT01458951, respectively).

Tofacitinib, an Oral Janus Kinase Inhibitor: Analysis of Malignancy (Excluding Nonmelanoma Skin Cancer) Events Across the Ulcerative Colitis Clinical Program.

BACKGROUND: Tofacitinib is an oral, small molecule Janus kinase inhibitor for the treatment of ulcerative colitis (UC). Here, we performed an integrated analysis of malignancy events from the tofacitinib phase 3 UC clinical development program (excluding nonmelanoma skin cancer [NMSC]). METHODS: Data (up to May 2019) were pooled from two phase 3 induction studies, a phase 3 maintenance study, and an ongoing, open-label, long-term extension (OLE) study, and analyzed as 3 cohorts: induction (N = 1139), maintenance (N = 592), and overall (induction, maintenance, and ongoing OLE study; N = 1124). Proportions and incidence rates (IRs; unique patients with events per 100 patient-years [PY] of exposure) for malignancies confirmed by adjudication were calculated. RESULTS: The overall cohort consisted of patients who received at least 1 dose of tofacitinib at 5 or 10 mg twice daily, for up to 6.8 years, with an exposure of 2576.4 PY. Of the 1124 overall cohort tofacitinib-treated patients, 20 developed a malignancy (excluding NMSC; IR, 0.75; 95% confidence interval, 0.46-1.16), of which 17 occurred in patients treated with tofacitinib 10 mg twice daily; importantly, more than 80% of patients predominantly received this dose. Furthermore, there was no apparent clustering of malignancy types, and IRs were stable over time. CONCLUSIONS: In the tofacitinib UC clinical development program, malignancy events were infrequent, and rates were comparable with those in the tofacitinib rheumatoid arthritis and psoriatic arthritis clinical development programs, and for biologic UC treatments. ClinicalTrials.gov: NCT01465763, NCT01458951, NCT01458574, and NCT01470612.

Herpes Zoster Infection in Patients With Ulcerative Colitis Receiving Tofacitinib.

Background: Tofacitinib is an oral, small molecule Janus kinase inhibitor that is being investigated for ulcerative colitis (UC). Tofacitinib is approved for rheumatoid arthritis and psoriatic arthritis, where it has been shown to increase herpes zoster (HZ) risk. We evaluated HZ risk among UC patients using tofacitinib. Methods: HZ cases were identified in tofacitinib phase II/III/ongoing, open-label, long-term extension (OLE) UC trials. We calculated HZ incidence rates (IRs) per 100 patient-years of tofacitinib exposure within phase III maintenance (Maintenance Cohort) and phase II/III/OLE (Overall Cohort) studies, stratified by baseline demographics and other factors. HZ risk factors were evaluated in the Overall Cohort using Cox proportional hazard models. Results: Overall, 65 (5.6%) patients developed HZ. Eleven patients had multidermatomal involvement (2 nonadjacent or 3-6 adjacent dermatomes), and 1 developed encephalitis (resolved upon standard treatment). Five (7.7%) events led to treatment discontinuation. HZ IR (95% confidence interval [CI]) in the Overall Cohort was 4.07 (3.14-5.19) over a mean (range) of 509.1 (1-1606) days, with no increased risk observed with increasing tofacitinib exposure. IRs (95% CI) were highest in patients age ≥65 years, 9.55 (4.77-17.08); Asian patients, 6.49 (3.55-10.89); patients with prior tumor necrosis factor inhibitor (TNFi) failure, 5.38 (3.86-7.29); and patients using tofacitinib 10 mg twice daily, 4.25 (3.18-5.56). Multivariate analysis identified older age and prior TNFi failure as independent risk factors. Conclusions: In tofacitinib-treated UC patients, there was an elevated risk of HZ, although complicated HZ was infrequent. Increased HZ rates occurred in patients who were older, Asian, or had prior TNFi failure (NCT00787202, NCT01465763, NCT01458951, NCT01458574, NCT01470612).

The diverse therapeutic actions of pregabalin: is a single mechanism responsible for several pharmacological activities?

Pregabalin is a specific ligand of the alpha2-delta (α2-δ) auxiliary subunit of voltage-gated calcium channels. A growing body of evidence from studies of anxiety and pain indicate that the observed responses with pregabalin may result from activity at the α2-δ auxiliary protein expressed presynaptically, in several different circuits of the central nervous system (CNS). The disorders that appear to be effectively treated with pregabalin are thematically linked by neuronal dysregulation or hyperexcitation within the CNS. This review proposes how binding to the α2-δ protein target in different regions of the CNS may contribute to the observed clinical activity of pregabalin, as well as to the adverse event profile of the compound. Whether this compound regulates synaptic function via α2-δ in additional conditions is yet to be discovered. The potential of pregabalin to regulate neuronal hyperactivity involving other CNS circuits will require further exploration.

Possible sites of therapeutic action in restless legs syndrome: focus on dopamine and α2δ ligands.

Restless legs syndrome (RLS) is a common sensorimotor disorder characterized by abnormal sensations that occur primarily at rest or during sleep, which are alleviated by movement of the affected limb. The pathophysiology of RLS remains unclear, although roles for dopamine dysfunction and brain iron deficiency have been proposed. The hypothalamic A11 dopaminergic circuit is used to explain the dopamine dysfunction in RLS and the potential therapeutic actions of dopamine D(2) agonists. Modulation of central and peripheral neuronal circuits may also explain the potential therapeutic sites of action of opioids, adenosine receptor ligands, and voltage-gated calcium channel α(2)δ ligands in RLS. The known and possible therapeutic benefits of these agents and their relationship to dopaminergic dysfunction in RLS are discussed in this review.

The alpha2-delta protein: an auxiliary subunit of voltage-dependent calcium channels as a recognized drug target.

Currently, there are two drugs on the market, gabapentin (Neurontin) and pregabalin (Lyrica), that are proposed to exert their therapeutic effect through binding to the alpha2-delta subunit of voltage-sensitive calcium channels. This activity was unexpected, as the alpha2-delta subunit had previously been considered not to be a pharmacological target. In this review, the role of the alpha2-delta subunits is discussed and the mechanism of action of the alpha2-delta ligands in vitro and in vivo is summarized. Finally, new insights into the mechanism of drugs that bind to this protein are discussed.

FAAH-/- mice display differential tolerance, dependence, and cannabinoid receptor adaptation after delta 9-tetrahydrocannabinol and anandamide administration.

Repeated administration of Delta(9)-tetrahydrocannabinol (THC), the primary psychoactive constituent of Cannabis sativa, induces profound tolerance that correlates with desensitization and downregulation of CB(1) cannabinoid receptors in the CNS. However, the consequences of repeated administration of the endocannabinoid N-arachidonoyl ethanolamine (anandamide, AEA) on cannabinoid receptor regulation are unclear because of its rapid metabolism by fatty acid amide hydrolase (FAAH). FAAH(-/-) mice dosed subchronically with equi-active maximally effective doses of AEA or THC displayed greater rightward shifts in THC dose-effect curves for antinociception, catalepsy, and hypothermia than in AEA dose-effect curves. Subchronic THC significantly attenuated agonist-stimulated [(35)S]GTP gamma S binding in brain and spinal cord, and reduced [(3)H]WIN55,212-2 binding in brain. Interestingly, AEA-treated FAAH(-/-) mice showed less CB(1) receptor downregulation and desensitization than THC-treated mice. Experiments examining tolerance and cross-tolerance indicated that the behavioral effects of THC, a low efficacy CB(1) receptor agonist, were more sensitive to receptor loss than those of AEA, a higher efficacy agonist, suggesting that the expression of tolerance was more affected by the intrinsic activity of the ligand at testing than during subchronic treatment. In addition, the CB(1) receptor antagonist, rimonabant, precipitated a markedly reduced magnitude of withdrawal in FAAH(-/-) mice treated subchronically with AEA compared with mice treated repeatedly with THC. The findings that repeated AEA administration produces lesser adaptive changes at the CB(1) receptor and has reduced dependence liability compared with THC suggest that pharmacotherapies targeting endocannabinoid catabolic enzymes are less likely to promote tolerance and dependence than direct acting CB(1) receptor agonists.

Hippocampal CB(1) receptors mediate the memory impairing effects of Delta(9)-tetrahydrocannabinol.

It is firmly established that the hippocampus, a brain region implicated in spatial learning, episodic memory, and consolidation, contains a high concentration of CB(1) receptors. Moreover, systemic and intrahippocampal administration of cannabinoid agonists have been shown to impair hippocampal-dependent memory tasks. However, the degree to which CB(1) receptors in the hippocampus play a specific functional role in the memory disruptive effects of marijuana or its primary psychoactive constituent Delta(9)-tetrahydrocannabinol (Delta(9)-THC) is unknown. This study was designed to determine whether hippocampal CB(1) receptors play a functional role in the memory disruptive effects of systemically administered cannabinoids, using the radial arm maze, a well characterized rodent model of working memory. Male Sprague-Dawley rats were implanted with bilateral cannulae aimed at the CA1 region of the dorsal hippocampus. The CB(1) receptor antagonist, rimonabant, was delivered into the hippocampus before to a systemic injection of either Delta(9)-THC or the potent cannabinoid analog, CP-55,940. Strikingly, intrahippocampal administration of rimonabant completely attenuated the memory disruptive effects of both cannabinoids in the radial arm maze task, but did not affect other pharmacological properties of cannabinoids, as assessed in the tetrad assay (that is, hypomotility, analgesia, catalepsy, and hypothermia). Infusions of rimonabant just dorsal or ventral to the hippocampus did not prevent Delta(9)-THC-induced memory impairment, indicating that its effects on mnemonic function were regionally selective. These findings provide compelling evidence in support of the view that hippocampal CB(1) receptors play a necessary role in the memory disruptive effects of marijuana.

Oxadiazolone bioisosteres of pregabalin and gabapentin.

A series of oxadiazolone bioisosteres of pregabalin 1 and gabapentin 2 were prepared, and several were found to exhibit similar potency for the alpha(2)-delta subunit of voltage-gated calcium channels. Oxadiazolone 9 derived from 2 achieved low brain uptake but was nevertheless active in models of osteoarthritis. The high clearance associated with compound 9 was postulated to be a consequence of efflux by OAT and/or OCT, and was attenuated on co-administration with cimetidine or probenecid.

Differential endocannabinoid regulation of extinction in appetitive and aversive Barnes maze tasks.

CB 1 receptor-compromised animals show profound deficits in extinguishing learned behavior from aversive conditioning tasks, but display normal extinction learning in appetitive operant tasks. However, it is difficult to discern whether the differential involvement of the endogenous cannabinoid system on extinction results from the hedonics or the required responses associated with the disparate tasks. Here, we report that the CB 1 receptor antagonist rimonabant disrupts extinction learning in an aversive, but not in an appetitive, Barnes maze conditioning task. Accordingly, these results provide compelling support for the hypothesis that the endogenous cannabinoid system plays a necessary role in the extinction of aversively motivated behaviors but is expendable for appetitively motivated behaviors.

The disruptive effects of the CB1 receptor antagonist rimonabant on extinction learning in mice are task-specific.

RATIONALE: Disruption of CB(1) receptor signaling through the use of CB(1) (-/-) mice or the CB(1) receptor antagonist rimonabant (SR141716) has been demonstrated to impair extinction of learned responses in conditioned fear and Morris water maze tasks. In contrast, CB(1) (-/-) mice exhibited normal extinction rates in an appetitively motivated operant conditioning task. OBJECTIVES: The purpose of this study was to test whether rimonabant would differentially disrupt extinction learning between fear-motivated and food-motivated tasks. MATERIALS AND METHODS: Separate groups of C57BL/6J mice were trained in two aversively motivated tasks, conditioned freezing and passive avoidance, and an appetitively motivated operant conditioning task at a fixed ratio (FR-5) schedule of food reinforcement. After acquisition, the respective reinforcers in each task were withheld, and an intraperitoneal injection of vehicle or rimonabant was given 30 min before each extinction session. RESULTS: Rimonabant (3 mg/kg) treatment significantly disrupted extinction in both the conditioned freezing and passive avoidance tasks but failed to affect extinction rates in the operant conditioning task, whether using daily or weekly extinction sessions. Interestingly, rimonabant (3 mg/kg) prevented the significant increases in lever pressing (i.e., extinction burst) that occurred during the first extinction session of the operant conditioning task. CONCLUSIONS: These results support the hypothesis that the CB(1) receptor plays a vital role in the extinction of aversive memories but is not essential for extinction of learned responses in appetitively motivated tasks.

Carboxylate bioisosteres of pregabalin.

Several beta-amino tetrazole analogs of gabapentin 1 and pregabalin 2 were prepared by one of two convergent, highly efficient routes, and their affinity for the alpha(2)-delta protein examined. Two select compounds with potent affinity for alpha(2)-delta, 8a and 16a, were subsequently tested in vivo in an audiogenic seizure model and found to elicit protective effects.

Structure-activity relationships of pregabalin and analogues that target the alpha(2)-delta protein.

Pregabalin exhibits robust activity in preclinical assays indicative of potential antiepileptic, anxiolytic, and antihyperalgesic clinical efficacy. It binds with high affinity to the alpha(2)-delta subunit of voltage-gated calcium channels and is a substrate of the system L neutral amino acid transporter. A series of pregabalin analogues were prepared and evaluated for their alpha(2)-delta binding affinity as demonstrated by their ability to inhibit binding of [(3)H]gabapentin to pig brain membranes and for their potency to inhibit the uptake of [(3)H]leucine into CHO cells, a measure of their ability to compete with the endogenous substrate at the system L transporter. Compounds were also assessed in vivo for their ability to promote anxiolytic, analgesic, and anticonvulsant actions. These studies suggest that distinct structure activity relationships exist for alpha(2)-delta binding and system L transport inhibition. However, both interactions appear to play an important role in the in vivo profile of these compounds.

Novel cyclopropyl beta-amino acid analogues of pregabalin and gabapentin that target the alpha2-delta protein.

As part of a program aimed at generating compounds with affinity for the alpha(2)-delta subunit of voltage-gated calcium channels, several novel beta-amino acids were prepared using an efficient nitroalkane-mediated cyclopropanation as a key step. Depending on the ester that was chosen, the target amino acids could be prepared in as few as three steps. The cyclopropyl amino acids derived from ketones proved to be potent binders of the alpha(2)-delta subunit of voltage-gated calcium channels, but did not interact with the large neutral amino acid system L (leucine) transporter. Anticonvulsant effects were observed in vivo with compound 34 but only after intracerebroventricular (icv) administration, presumably due to inadequate brain concentrations of the drug being achieved following oral dosing. However, pregabalin 1 was active in the DBA/2 model after oral (and icv) dosing, supporting a hypothesis that active transport is a prerequisite for such zwitterionic species to cross the blood-brain barrier.

Peptides that regulate food intake: regional, metabolic, and circadian specificity of lateral hypothalamic orexin A feeding stimulation.

Orexin A (OX-A) administered in the lateral hypothalamus (LH) increases feeding in a dose-dependent manner. The LH is a relatively large neural structure with a heterogeneous profile of neural inputs, efferent projections, and orexin receptor distribution. We sought to determine the LH region most sensitive to the feeding stimulatory effect of OX-A injection. Fifty-six male Sprague-Dawley rats were fitted with cannulas 1 mm above four separate LH regions approximately 1 mm apart in the rostral-caudal direction. There were 14-16 animals/LH region. After recovery, animals received either artificial cerebrospinal fluid or OX-A (250, 500, or 1,000 pmol). To determine whether there is a circadian effect of LH OX-A on the feeding response, we performed injections at 0200, 0900, 1400, and 2100. Food intake was measured at 1, 2, and 4 h after injection. The most rostral extent of the LH was the only region in which injection of OX-A significantly stimulated feeding. Within this region, feeding was increased at all times of the day, although the most robust and only significant feeding response occurred after the afternoon injection (1400) of OX-A. To determine the extent to which the metabolic status of the rat contributed to the circadian specificity of orexin-induced feeding, animals were placed on a restricted diet and injected with OX-A in the most rostral region of the LH. Under these conditions, OX-A significantly increased feeding and more robustly when compared with animals on a nonrestricted diet. These data suggest that the rostral LH is the only region of the LH sensitive to the injection of OX-A, and the metabolic status of the animal at the time of injection may influence the feeding response to OX-A.