1
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Taylor TL, Smith BP, Hazel SJ. Guardians' perceptions of caring for a dog with canine cognitive dysfunction. Vet Rec 2024; 194:e3266. [PMID: 37503693 DOI: 10.1002/vetr.3266] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2022] [Revised: 06/04/2023] [Accepted: 07/04/2023] [Indexed: 07/29/2023]
Abstract
BACKGROUND Canine cognitive dysfunction (CCD) is a neurodegenerative disease that is difficult to diagnose, as its clinical signs are similar to those of other age-related conditions. The experience of caring for a senior dog with or without CCD is not well described. METHODS Data were collected via an online survey. Using a mixed methods design, the level of CCD and burden of care were measured using validated tools, and open-ended questions gathered qualitative data. A general linear model showed the factors associated with guardian burden of care. RESULTS Sixteen percent of guardians experienced a clinically significant burden of care. Factors associated with burden of care included severity of CCD, sleep location, guardian employment, household size, dog age, guardian age and the dog taking medication. Few dogs with CCD were prescribed CCD medications to ameliorate clinical signs. Euthanasia, strong attachment mitigating burden and the complexities of caregiving were themes presented by guardians. LIMITATIONS Measures are based on self-reports and as such the usual limitations apply. CONCLUSIONS The burden of caring for an older dog is greater if they have CCD. More attention to the treatment of senior dogs, including medications to reduce clinical signs of CCD, could improve the welfare of older dogs and decrease the clinical burden experienced by guardians.
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Affiliation(s)
- Tracey L Taylor
- Faculty of Sciences, Engineering and Technology, School of Animal and Veterinary Sciences, University of Adelaide, Adelaide, South Australia, Australia
| | - Bradley P Smith
- College of Psychology, School of Human Health and Social Sciences, Central Queensland University Australia, Wayville, South Australia, Australia
| | - Susan J Hazel
- Faculty of Sciences, Engineering and Technology, School of Animal and Veterinary Sciences, University of Adelaide, Adelaide, South Australia, Australia
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2
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Haake J, Meyerhoff N, Meller S, Twele F, Charalambous M, Wilke V, Volk H. Investigating Owner Use of Dietary Supplements in Dogs with Canine Cognitive Dysfunction. Animals (Basel) 2023; 13:3056. [PMID: 37835662 PMCID: PMC10571926 DOI: 10.3390/ani13193056] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2023] [Revised: 09/10/2023] [Accepted: 09/28/2023] [Indexed: 10/15/2023] Open
Abstract
Canine cognitive dysfunction (CCD) is becoming increasingly recognized in veterinary medicine, as dogs live longer and with CCD being highly prevalent among the elderly dog population. Various studies have shown that diet and dietary supplementation can positively influence the clinical signs of CCD, especially if given at an early stage. The aim of this study was to investigate owner use of dietary supplements (DSs) in dogs with age-related behavioral changes. An observational study based on an online questionnaire for owners of dogs with age-related behavioral changes was performed. Out of a total of 394 owners who completed the survey, after noticing age-related behavioral changes, over half of the dogs received DSs (54%), whereas only 8% reported changing their dog's base diet. The most used DS was fish oil (48%). The use of DSs should be discussed with and monitored by veterinary surgeons since many geriatric patients have multi-morbidities, may have specific nutritional requirements and receive multi-faceted medications.
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Affiliation(s)
- Julia Haake
- Department of Small Animal Medicine and Surgery, University of Veterinary Medicine Hannover, 30559 Hannover, Germany; (J.H.); (N.M.); (S.M.); (F.T.); (M.C.)
| | - Nina Meyerhoff
- Department of Small Animal Medicine and Surgery, University of Veterinary Medicine Hannover, 30559 Hannover, Germany; (J.H.); (N.M.); (S.M.); (F.T.); (M.C.)
| | - Sebastian Meller
- Department of Small Animal Medicine and Surgery, University of Veterinary Medicine Hannover, 30559 Hannover, Germany; (J.H.); (N.M.); (S.M.); (F.T.); (M.C.)
| | - Friederike Twele
- Department of Small Animal Medicine and Surgery, University of Veterinary Medicine Hannover, 30559 Hannover, Germany; (J.H.); (N.M.); (S.M.); (F.T.); (M.C.)
| | - Marios Charalambous
- Department of Small Animal Medicine and Surgery, University of Veterinary Medicine Hannover, 30559 Hannover, Germany; (J.H.); (N.M.); (S.M.); (F.T.); (M.C.)
| | - Volker Wilke
- Institute for Animal Nutrition, University of Veterinary Medicine, Foundation, 30173 Hannover, Germany;
| | - Holger Volk
- Department of Small Animal Medicine and Surgery, University of Veterinary Medicine Hannover, 30559 Hannover, Germany; (J.H.); (N.M.); (S.M.); (F.T.); (M.C.)
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3
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Sordo L, Gunn-Moore DA. Cognitive Dysfunction in Cats: Update on Neuropathological and Behavioural Changes Plus Clinical Management. Vet Rec 2021; 188:e3. [PMID: 34651755 DOI: 10.1002/vetr.3] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
Cognitive dysfunction syndrome (CDS) is an established condition in cats that shares many similarities with human Alzheimer's disease (AD), where cognitive decline ultimately results in dementia. Cats with CDS display behavioural abnormalities, including excessive Vocalisation, altered Interaction with owners (increased affection/attention), altered Sleep-wake cycles, House-soiling, Disorientation (spatial and/or temporal), alterations in Activity, Anxiety, and/or Learning/memory deficits (i.e., VISHDAAL). These cats develop neuropathologies, such as accumulation of β-amyloid and hyperphosphorylated tau deposits. Because of its similarities to those in the brains of people with cognitive impairment and AD, the domestic cat could be a natural model for human dementia studies. It is important to diagnose CDS promptly in cats, ruling out other causes for these behavioural changes, to provide effective management. Interventions include environmental enrichment (e.g., easy access to key resources, calming pheromones), dietary supplementations (e.g., Senilife, Aktivait for cats, SAMe), specific diets (e.g., containing antioxidants, medium-chain triglycerides) and, potentially, medication (e.g., selegiline or propentofylline). This article reviews the literature about CDS in cats, its causes, neuropathology, clinical signs, diagnosis and potential management options. By doing so, it furthers our understanding of this condition and allows improved health, welfare and quality of life of affected cats.
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Affiliation(s)
- Lorena Sordo
- The Royal (Dick) School of Veterinary Studies and The Roslin Institute, The University of Edinburgh, Easter Bush Campus, Roslin, UK
| | - Danièlle A Gunn-Moore
- The Royal (Dick) School of Veterinary Studies and The Roslin Institute, The University of Edinburgh, Easter Bush Campus, Roslin, UK
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4
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Dewey CW, Davies ES, Xie H, Wakshlag JJ. Canine Cognitive Dysfunction: Pathophysiology, Diagnosis, and Treatment. Vet Clin North Am Small Anim Pract 2019; 49:477-499. [PMID: 30846383 DOI: 10.1016/j.cvsm.2019.01.013] [Citation(s) in RCA: 38] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Canine cognitive dysfunction (CCD) is the canine analog of human Alzheimer disease (AD). The pathophysiology of CCD/AD is multifaceted. CCD is common in aged (>8 years) dogs, affecting between 14% and 35% of the pet dog population. Apparent confusion, anxiety, disturbance of the sleep/wake cycle, and decreased interaction with owners are all common clinical signs of CCD. Although there is no cure for CCD, several proven effective therapeutic approaches are available for improving cognitive ability and maintaining a good quality of life; instituting such therapies early in the disease course is likely to have the greatest positive clinical effect.
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Affiliation(s)
- Curtis Wells Dewey
- Department of Clinical Sciences, College of Veterinary Medicine, Cornell University, C4 169 Clinical Programs Center, Ithaca, NY 14853, USA.
| | - Emma S Davies
- Department of Clinical Sciences, College of Veterinary Medicine, Cornell University, C4 169 Clinical Programs Center, Ithaca, NY 14853, USA
| | - Huisheng Xie
- Department of Small Animal Clinical Sciences, College of Veterinary Medicine, University of Florida, Gainesville, FL, USA; Department of Comparative, Diagnostic and Population Medicine, 9700 Highway 318 West, Reddick, FL 32686, USA
| | - Joseph J Wakshlag
- Department of Small Animal Clinical Sciences, College of Veterinary Medicine, University of Florida, Gainesville, FL, USA; Department of Comparative, Diagnostic and Population Medicine
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5
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Grigg EK, Hart LA. Enhancing Success of Veterinary Visits for Clients With Disabilities and an Assistance Dog or Companion Animal: A Review. Front Vet Sci 2019; 6:44. [PMID: 30859106 PMCID: PMC6397855 DOI: 10.3389/fvets.2019.00044] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2018] [Accepted: 02/04/2019] [Indexed: 01/29/2023] Open
Abstract
Despite increasing information on enhancing client communication and compliance/adherence in veterinary medicine, literature focusing on special cases remains limited: working with clients with special needs, challenges or disabilities, or when the patient is an assistance or emotional support animal. This paper summarizes current recommendations on how best to build successful working relationships with these clients, including action items to implement in practice. In addition, this paper reviews current literature on important considerations for care of assistance dogs as patients.
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Affiliation(s)
- Emma K Grigg
- Department of Population Health and Reproduction, School of Veterinary Medicine, University of California, Davis, Davis, CA, United States
| | - Lynette A Hart
- Department of Population Health and Reproduction, School of Veterinary Medicine, University of California, Davis, Davis, CA, United States
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6
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Rajapaksha E. Special Considerations for Diagnosing Behavior Problems in Older Pets. Vet Clin North Am Small Anim Pract 2018; 48:443-456. [PMID: 29422408 DOI: 10.1016/j.cvsm.2017.12.010] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Abstract
Aging is a complex process that involves changes in sensory perception, cognition, and physical strength. Physiologic, metabolic, and emotional changes of the aging process can lead to behavioral problems in older pets. Treatment of behavior problems in older pets requires a multimodal therapeutic approach. Frequent follow-up visits are required to monitor pets and comment on prognosis. Clients should be informed of the prognosis and should be educated to evaluate pain, discomfort, and general quality of life of the aging pet.
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Affiliation(s)
- Eranda Rajapaksha
- Veterinary Clinical Sciences, University of Peradeniya, Peradeniya 20400, Sri Lanka.
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7
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Miklya I. The significance of selegiline/(-)-deprenyl after 50 years in research and therapy (1965-2015). Mol Psychiatry 2016; 21:1499-1503. [PMID: 27480491 DOI: 10.1038/mp.2016.127] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/02/2015] [Revised: 11/30/2015] [Accepted: 12/15/2015] [Indexed: 11/09/2022]
Abstract
Deprenyl/Selegiline (DEP), created by Joseph Knoll in the 1960s, registered in more than 60 countries to treat Parkinson's disease, Alzheimer's disease, major depressive disorder; and used as an anti-aging drug, achieved its place in research and therapy as the first selective inhibitor of B-type monoamine oxidase (MAO-B). The demonstration that the DEP analog (-)-1-phenyl-2-propylaminopentane devoid of MAO inhibitory property, enhanced like DEP the activity of the catecholaminergic brain engine revealed that this effect is unrelated to the selective inhibition of MAO-B. β-Phenylethylamine (PEA), the important trace-amine in the mammalian brain, is known to be a releaser of catecholamines. Amphetamine and methamphetamine, the best known synthetic PEA derivatives are also releasers of catecholamines like their parent compound. DEP is a unique synthetic PEA derivative devoid of the catecholamine releasing property. As the releasing effect conceals the catecholaminergic activity enhancer (CAE) effect, it remained undiscovered until DEP uncovered that PEA is a natural CAE substance; and only releases catecholamines in high concentration. Discovering that tryptamine is a natural enhancer of catecholaminergic and serotonergic neurons catalyzed the development of R-(-)-1-(benzofuran-2-yl)-2-propylaminopentane (BPAP); the most potent and selective enhancer substance, and it exerts its enhancer effect in 0.0001 mg kg-1. DEP and BPAP initiated an analysis of the enhancer regulation in the mammalian brain. Studies regarding the nature of the enhancer regulation revealed that this regulation is enhanced after weaning and sex hormones return it to the pre-weaning level. Thus, sex hormones elicit the transition of the developmental phase of life into the post-developmental, downhill (aging) period. The aging-related, slow decline in the enhancer regulation of the catecholaminergic brain engine, the main activator of the cortex, is the prime factor of brain aging. The enhancer regulation's decay in the most rapidly aging dopaminergic system is, for example, mainly responsible for the decline in learning ability and sexual activity over time. According to the Knoll concept, based on two longevity studies performed on male rats, to keep the catecholaminergic brain engine, from the beginning of the downhill period of life, via the administration of a small daily dose of a CAE substance (presently DEP is the only available drug) on a higher activity level, thus to fight against the physiological aging-related slow decay of the catecholaminergic system, is a suitable anti-aging therapy. As our present knowledge regarding the enhancer regulation in the mammalian brain is like seeing a peak of an iceberg, the future of this new line of brain research looks promising from both theoretical and practical aspects.
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Affiliation(s)
- I Miklya
- Department of Pharmacology and Pharmacotherapy, Semmelweis University, Budapest, Hungary
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8
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A novel mechanism for cognitive enhancement in aged dogs with the use of a calcium-buffering protein. J Vet Behav 2015. [DOI: 10.1016/j.jveb.2015.02.003] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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9
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Denham HDC, Bradshaw JWS, Rooney NJ. Repetitive behaviour in kennelled domestic dog: stereotypical or not? Physiol Behav 2014; 128:288-94. [PMID: 24472323 DOI: 10.1016/j.physbeh.2014.01.007] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2013] [Revised: 12/18/2013] [Accepted: 01/14/2014] [Indexed: 11/25/2022]
Abstract
Repetitive behaviour is common in kennelled dogs, yet its motivational basis remains relatively unexplored. We examine the repetitive behaviour of 30 kennelled working dogs in ten contexts both coinciding with, and in the absence of, commonly occurring arousing stimuli, such as care staff, other dogs and food preparation. A large proportion (93%) of subjects performed some repetitive behaviour, most commonly bouncing, but only 17% in the absence of the arousing stimuli. Subjects could be divided into four groups according to the stimuli eliciting, and the duration, of their repetitive behaviour, and these groups were compared on the basis of their cortisol response to an acute psychogenic stressor--a veterinary examination. Urinary cortisol/creatinine response curves differed significantly between the groups. In particular, those dogs which performed repetitive behaviour at times of minimal stimulation, showed a distinctly different pattern of response, with cortisol levels decreasing, as compared to increasing, after the veterinary examination. We conclude that dogs showing repetitive behaviours at times of high arousal are motivationally distinct from those "stereotyping" in the absence of stimulation. We suggest that those dogs showing spontaneous repetitive behaviours may have past experiences and/or temperaments that affect both their reactions to a veterinary examination and to long-term kennelling. For example, some dogs may find isolation from humans particularly aversive, hence affecting their reactions both to being left in a kennel and to being taken to the veterinary surgeon. Alternatively, such dogs may have atypical responsiveness of their hypothalamic-pituitary-adrenal (HPA) axis, possibly brought about through chronic stress. High levels of repetitive behaviours in response to inaccessible husbandry events may be explained if such behaviour has inadvertently been reinforced by attention from staff, and therefore may not always be indicative of aversion to kennelling or compromised welfare.
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Affiliation(s)
- Hamish D C Denham
- Royal (Dick) School of Veterinary Studies, The University of Edinburgh, Easter Bush Veterinary Centre, Roslin, EH25 9RG, United Kingdom; Royal Army Veterinary Corps, Royal Army Medical Directorate, Army Headquarters, Former Army Staff College, Slim Road, Camberley, Surrey GU15 4NP, United Kingdom.
| | - John W S Bradshaw
- Anthrozoology Institute, Animal Welfare and Behaviour Group, University of Bristol, School of Veterinary Sciences, Langford BS40 5DU, United Kingdom
| | - Nicola J Rooney
- Anthrozoology Institute, Animal Welfare and Behaviour Group, University of Bristol, School of Veterinary Sciences, Langford BS40 5DU, United Kingdom.
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10
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Landsberg GM, Nichol J, Araujo JA. Cognitive Dysfunction Syndrome. Vet Clin North Am Small Anim Pract 2012; 42:749-68, vii. [DOI: 10.1016/j.cvsm.2012.04.003] [Citation(s) in RCA: 79] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
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11
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Landsberg GM, Deporter T, Araujo JA. Clinical signs and management of anxiety, sleeplessness, and cognitive dysfunction in the senior pet. Vet Clin North Am Small Anim Pract 2012; 41:565-90. [PMID: 21601747 DOI: 10.1016/j.cvsm.2011.03.017] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
Physical signs of old age may be obvious, but mental and cognitive changes require more careful observation. Changes in behavior may represent the earliest indications of medical problems, or disorders of the central nervous system, and these may be bidirectional. Cognitive dysfunction syndrome is underdiagnosed and affects a substantial portion of aged companion animals. This article describes potential treatment regimens to address age-related behavioral problems, as well as a framework for investigating differential diagnoses. Early identification of changes in behavior is essential for the adequate treatment and management of medical and behavioral problems, and for monitoring outcomes.
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Affiliation(s)
- Gary M Landsberg
- North Toronto Animal Clinic, 99 Henderson Avenue, Thornhill, ON L3T 2K9, Canada.
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12
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Manteca X. Nutrition and behavior in senior dogs. Top Companion Anim Med 2011; 26:33-6. [PMID: 21435624 DOI: 10.1053/j.tcam.2011.01.003] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2010] [Accepted: 01/07/2011] [Indexed: 11/11/2022]
Abstract
With increasing age, some dogs develop a neurogenerative disease that is commonly referred to as canine cognitive dysfunction syndrome (CDS). Diagnosis of CDS can be clinical or based on laboratory tests. The main behavioral changes associated with CDS are disorientation, altered interactions with people or other animals, sleep-wake cycle alterations, house-soiling, and changes in activity level. Ruling out medical conditions that can cause similar changes in behavior is important when performing a clinical diagnosis. Management of CDS includes dietary and pharmacological intervention. Dietary treatment of CDS has been based on the use of antioxidants and mitochondrial cofactors, and recent work has shown that long-term supplementation with medium-chain triglycerides can improve cognitive function in aged dogs. CDS must be considered an animal welfare issue and the implications of this are discussed in this article.
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Affiliation(s)
- Xavier Manteca
- School of Veterinary Science, Universitat Autònoma de Barcelona, Barcelona, Spain.
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13
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Landsberg GM, Denenberg S, Araujo JA. Cognitive dysfunction in cats: a syndrome we used to dismiss as 'old age'. J Feline Med Surg 2010; 12:837-48. [PMID: 20974401 PMCID: PMC11220932 DOI: 10.1016/j.jfms.2010.09.004] [Citation(s) in RCA: 53] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
PRACTICAL RELEVANCE Cognitive dysfunction syndrome (CDS) is a widely accepted diagnosis in dogs, with established treatment options. In cats, however, our understanding of cognitive dysfunction is still being shaped by ongoing research in the field, and limited treatment options are available. Recent clinical studies indicate that old age in the cat is accompanied by increased behavioural signs such as wandering, vocalization and night-time activity that are not attributable to identifiable medical problems. It is essential, therefore, that veterinarians include behavioural well-being in the routine care of senior cats. PATIENT GROUP While the exact age of onset is not established, studies suggest that age-related behavioural changes consistent with cognitive dysfunction are prevalent in cats as early as 10 years of age and that prevalence increases significantly in older cats. CLINICAL CHALLENGES The diagnosis of cognitive dysfunction requires the identification of geriatric behavioural changes that are not caused by other medical problems, although the two may not be mutually exclusive. Therefore, the practitioner must rely heavily on owner reports and history to ensure prompt diagnosis and treatment. The absence of any approved dietary or pharmaceutical interventions for cognitive dysfunction adds a further challenge, although several possibilities exist. EVIDENCE BASE This article draws on recent research that has produced neuropathological, cognitive and behavioural evidence for cognitive dysfunction in aging cats. As an impetus to further our understanding of this disease and potential treatment options, the authors propose a behavioural checklist that might aid in the clinical diagnosis of feline CDS and discuss treatment options that have proven successful in the canine counterpart of this disease.
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Affiliation(s)
- Gary M Landsberg
- North Toronto Animal Clinic, Thornhill, Ontario L3T 2K9, Canada.
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Araujo JA, de Rivera C, Ethier JL, Landsberg GM, Denenberg S, Arnold S, Milgram NW. ANXITANE® tablets reduce fear of human beings in a laboratory model of anxiety-related behavior. J Vet Behav 2010. [DOI: 10.1016/j.jveb.2010.02.003] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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15
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Denenberg S, Landsberg G. Therapeutic options for treatment of Cognitive Dysfunction Syndrome in companion animals. J Vet Behav 2010. [DOI: 10.1016/j.jveb.2009.12.013] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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16
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Moscardo E, Fasdelli N, Giarola A, Tontodonati M, Dorigatti R. An optimised neurobehavioural observation battery integrated with the assessment of cardiovascular function in the beagle dog. J Pharmacol Toxicol Methods 2009; 60:198-209. [DOI: 10.1016/j.vascn.2009.05.005] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2009] [Accepted: 05/13/2009] [Indexed: 11/25/2022]
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Tontodonati M, Fasdelli N, Moscardo E, Giarola A, Dorigatti R. A canine model used to simultaneously assess potential neurobehavioural and cardiovascular effects of candidate drugs. J Pharmacol Toxicol Methods 2007; 56:265-75. [PMID: 17587603 DOI: 10.1016/j.vascn.2007.03.005] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2007] [Accepted: 03/30/2007] [Indexed: 11/22/2022]
Abstract
INTRODUCTION Unwanted effects of drugs on neurobehavioural and cardiovascular functions are normally assessed in separate studies and using different animals. A new model using dogs which allows for the integration of these assessments into a single study was established and validated, adopting the most sophisticated technologies for both monitoring behaviour by video recordings and cardiovascular parameters by telemetry. METHODS Conscious male beagle dogs (n=4) were given single oral doses of vehicle, and D-amphetamine (0.25, 0.75, 1.5 mg/kg) or acepromazine (0.05, 0.3, 2 mg/kg) within two different studies. Blood pressure, heart rate, electrocardiogram (EKG), body temperature, motor activity and behaviour (by video) were monitored continuously for 24 h post-dose. Animals underwent a full neurobehavioural examination the day before dosing, at the time to the maximal plasma concentration (Tmax) and 24 h post-dose. RESULTS D-Amphetamine: a dose-dependent increase in arterial blood pressure was noted at all doses and was generally associated with an increase in the QA interval, an index of cardiac contractility. Heart rate also increased but only at the 1.5 mg/kg dose. A dose-dependent general excitatory state of the nervous system was observed, characterised mainly by hyper-reactivity, and stereotyped activities. Acepromazine: a decrease in systolic blood pressure was detected at 0.3 and 2 mg/kg generally associated with a decrease in pulse pressure reflecting a negative inotropic effect. A dose-related increase in heart rate accompanied this effect. Dose-dependent general depression of the nervous system was noted; mainly characterised by half-closed eyes, subdued behaviour and impaired posture. In both studies, all dogs completely recovered at approximately 16 h after treatment. DISCUSSION Cardiovascular and neurobehavioural changes expected from the pharmacology of test substances were accurately detected. No significant fluctuations of the telemetric parameters recorded were noted as a consequence of the handling associated with the direct neurobehavioural examination. These results confirm the validity of this combined model capable of providing a reliable neurobehavioural and cardiovascular assessment of drugs.
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MESH Headings
- Acepromazine/administration & dosage
- Acepromazine/pharmacology
- Acepromazine/toxicity
- Administration, Oral
- Animals
- Behavior, Animal/drug effects
- Behavior, Animal/physiology
- Blood Pressure/drug effects
- Body Temperature/drug effects
- Body Temperature/physiology
- Cardiovascular Physiological Phenomena/drug effects
- Dextroamphetamine/administration & dosage
- Dextroamphetamine/pharmacology
- Dextroamphetamine/toxicity
- Dogs
- Dose-Response Relationship, Drug
- Drugs, Investigational/administration & dosage
- Drugs, Investigational/pharmacology
- Drugs, Investigational/toxicity
- Electrocardiography/drug effects
- Electrocardiography/methods
- Heart Rate/drug effects
- Hyperkinesis/chemically induced
- Hyperkinesis/physiopathology
- Hypnotics and Sedatives/administration & dosage
- Hypnotics and Sedatives/pharmacology
- Hypnotics and Sedatives/toxicity
- Long QT Syndrome/chemically induced
- Long QT Syndrome/physiopathology
- Male
- Models, Animal
- Motor Activity/drug effects
- Motor Activity/physiology
- Reflex, Pupillary/drug effects
- Reflex, Pupillary/physiology
- Reproducibility of Results
- Sialorrhea/chemically induced
- Sialorrhea/physiopathology
- Telemetry/methods
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Affiliation(s)
- Marcello Tontodonati
- Safety Pharmacology, Safety Assessment Department, GlaxoSmithKline R&D Centre, Via A. Fleming 4, 37135 Verona, Italy.
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Abstract
Many treatment options are now available for pets with age-related cognitive dysfunction, including drugs, nutritional supplements, and diets. This article describes the theory, evidence of efficacy, and potential neuroprotective effects of products used to treat cognitive dysfunction. Cognitive dysfunction is a diagnosis of exclusion, because many painful conditions and health problems may present with similar signs. Practitioners must, therefore, actively question owners of senior pets in order to diagnose cognitive dysfunction and to assess the pet’s general health and well-being.
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Affiliation(s)
- Gary Landsberg
- Doncaster Animal Clinic, 99 Henderson Avenue, Thornhill, Ontario, L3T 2K9, Canada
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19
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Berry MD. R-2HMP: an Orally Active Agent Combining Independent Antiapoptotic and MAO-B-Inhibitory Activities. CNS DRUG REVIEWS 2006. [DOI: 10.1111/j.1527-3458.1999.tb00093.x] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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20
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Abstract
Aging pets often suffer a decline in cognitive function (eg, memory,learning, perception, awareness) likely associated with age-dependent brain alterations. Clinically, cognitive dysfunction may result in various behavioral signs, including disorientation; forgetting of previously learned behaviors, such as house training; alterations in the manner in which the pet interacts with people or other pets;onset of new fears and anxiety; decreased recognition of people, places, or pets; and other signs of deteriorating memory and learning ability. Many medical problems, including other forms of brain pathologic conditions, can contribute to these signs. The practitioner must first determine the cause of the behavioral signs and then determine an appropriate course of treatment, bearing in mind the constraints of the aging process. A diagnosis of cognitive dysfunction syndrome is made once other medical and behavioral causes are ruled out.
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Affiliation(s)
- Gary Landsberg
- Doncaster Animal Clinic, 99 Henderson Avenue, Thornhill, Ontario L3T2K9, Canada.
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Landsberg G. Therapeutic agents for the treatment of cognitive dysfunction syndrome in senior dogs. Prog Neuropsychopharmacol Biol Psychiatry 2005; 29:471-9. [PMID: 15795056 DOI: 10.1016/j.pnpbp.2004.12.012] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 12/13/2004] [Indexed: 01/10/2023]
Abstract
With increasing age, dogs develop a form of neurodegenerative disease which has many similarities to age related cognitive impairment and Alzheimer's disease in humans. A decline in learning and memory can be demonstrated in dogs beginning as young as 7 years of age using a variety of neuropsychological tests. However, clinical cases of cognitive dysfunction syndrome are seldom identified until the age of 11 years or older. This is likely due to the fact that the owners are relying on clinical observations such as house-soiling, sleep-wake cycles and disorientation, rather than tests of learning and memory. On the other hand, dogs that are trained to more exacting tasks such as guide dogs for the visually impaired, or bomb detection and agility trained dogs might be noticed to have a decline in performance at a much earlier age. Through the use of standardized neuropsychological testing protocols, a number of drugs, natural products and supplement formulations have been developed for use in dogs with cognitive dysfunction and, in some cases clinical trials have validated their efficacy. Furthermore, the testing of products currently licensed and in the pipeline for the treatment of cognitive decline and Alzheimer's in humans, may provide additional therapeutic agents for the treatment of senior dogs, as well as provide insight as to the potential for the efficacy of these compounds in humans. This review will examine those products that are now marketed along with some that might be considered for use in senior dogs with cognitive dysfunction as well as the research that has been used to validate the efficacy (or lack thereof) of these compounds.
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Affiliation(s)
- Gary Landsberg
- Doncaster Animal Clinic, 99 Henderson Avenue, Thornhill, Ontario, Canada L3T 2K9.
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Dodam JR, Cohn LA, Durham HE, Szladovits B. Cardiopulmonary effects of medetomidine, oxymorphone, or butorphanol in selegiline-treated dogs. Vet Anaesth Analg 2004; 31:129-37. [PMID: 15053751 DOI: 10.1111/j.1467-2987.2004.00164.x] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
OBJECTIVES To determine if chronic selegiline HCl administration affects the cardiopulmonary response to medetomidine, oxymorphone, or butorphanol in dogs. STUDY DESIGN Prospective randomized experimental study. ANIMALS Twenty-eight adult, random source, hound dogs weighing 21-33 kg. METHODS Dogs were assigned to the following treatment groups: selegiline + medetomidine (MED; n = 6); placebo + MED (n = 6), selegiline + oxymorphone (OXY; n = 6); placebo + OXY (n = 6); selegiline + butorphanol (BUT; n = 7) or placebo + BUT (n = 6). Nine dogs were treated with two of the three pre-medicants. Dogs were treated with selegiline (1 mg kg(-1) PO, q 24 hours) or placebo for at least 44 days prior to pre-medicant administration. On the day of the experiment, arterial blood for blood gas analysis, blood pressure measurements, ECG, cardiac ultrasound (mM-mode, 2-D, and continuous wave Doppler), and behavioral observations were obtained by blinded observers. An IV injection of MED (750 micro g m(-2)), OXY (0.1 mg kg(-1)) or BUT (0.4 mg kg(-1)) was given. Cardiopulmonary and behavioral data were collected at 1, 2, 5, 15, 30, and 60 minutes after injection. RESULTS Selegiline did not modify responses to any of the pre-medicant drugs. Medetomidine caused a significant decrease in heart rate (HR), cardiac output (CO), and fractional shortening (FS). Mean arterial pressure (MAP), systemic vascular resistance (SVR), and central venous pressure (CVP) were increased. Level of consciousness and resistance to restraint were both decreased. Oxymorphone did not affect MAP, CO, CVP, or SVR, but RR and PaCO(2) were increased. Level of consciousness and resistance to restraint were decreased. BUT decreased heart rate at 1 and 5 minutes. All other cardiovascular parameters were unchanged. BUT administration was associated with decreased arterial pH and increased PaCO(2). BUT decreased level of consciousness and resistance to restraint. CONCLUSIONS AND CLINICAL RELEVANCE Although pre-medicants themselves altered cardiopulmonary and behavioral function, selegiline did not affect the response to medetomidine, oxymorphone, or butorphanol in this group of normal dogs.
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Affiliation(s)
- John R Dodam
- Department of Veterinary Medicine and Surgery, College of Veterinary Medicine, University of Missouri, 379 East Campus Drive, Columbia, MO 65211, USA.
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Hashizume C, Suzuki M, Masuda K, Momozawa Y, Kikusui T, Takeuchi Y, Mori Y. Molecular cloning of canine monoamine oxidase subtypes A (MAOA) and B (MAOB) cDNAs and their expression in the brain. J Vet Med Sci 2003; 65:893-8. [PMID: 12951422 DOI: 10.1292/jvms.65.893] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The role of monoamine oxidase has been shown to be related to some behavioral changes including aggression and cognitive dysfunction. In order to demonstrate the basic expression patterns of monoamine oxidase in the canine brain, we determined the full-length nucleotide sequences of cDNA for canine monoamine oxidase type A (MAOA) and type B (MAOB) genes that were isolated from the canine brain cDNA library. Oligonucleotide primers for PCR were constructed based on the conserved sequences reported thus far for other mammalian species. The nucleotide sequences had open reading frames of 1584 and 1563 bp for MAOA and MAOB, respectively. Both of these genes showed relatively high homology with other species in both nucleotide (> 81%) and deduced amino acid (> 85%) sequences. In Northern blot analyses MAOA mRNA was expressed broadly in various parts of the canine brain, whereas MAOB mRNA was found only in specific brain regions, such as the hypothalamus, hippocampus, brain stem and olfactory bulb. These results suggest that MAOA and MAOB mRNAs have subtype-specific expression patterns in the canine brain.
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Affiliation(s)
- Chie Hashizume
- Laboratory of Veterinary Ethology, The University of Tokyo, Yayoi, Bunkyo-ku, Tokyo, Japan
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24
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Simpson BS, Papich MG. Pharmacologic management in veterinary behavioral medicine. Vet Clin North Am Small Anim Pract 2003; 33:365-404, vii. [PMID: 12701517 DOI: 10.1016/s0195-5616(02)00130-4] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
As our knowledge expands, behavioral pharmacology plays an increasingly important role in behavioral medicine. Drugs traditionally categorized as anxiolytics, antidepressants, anticonvulsants, and hormones may be used to help manage a range of animal behavioral problems. Knowledge of how these agents act in the body and interact with other agents is imperative for safe and efficacious use.
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25
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Cohn LA, Dodam JR, Szladovits B. Effects of selegiline, phenylpropanolamine, or a combination of both on physiologic and behavioral variables in healthy dogs. Am J Vet Res 2002; 63:827-32. [PMID: 12061528 DOI: 10.2460/ajvr.2002.63.827] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
OBJECTIVE To determine effects of selegiline hydrochloride, phenylpropanolamine (PPA), or a combination of both on physiologic and behavioral variables in dogs. ANIMALS 40 adult hound-type dogs. PROCEDURE Dogs were assigned to 4 groups. One group received selegiline (1 mg/kg, PO, q 24 h) and PPA (1.1 mg/kg, PO, q 8 h), a second group received selegiline alone, a third group received PPA alone, and a fourth group received neither drug. Dogs were observed 3 times/d throughout the 30-day study (daily during the first week, on alternate days during the next 2 weeks, and again daily during the final week). Observers recorded rectal temperature, pulse, respiratory rate, oscillometric blood pressure, and lead-II ECG and assessed 4 behaviors, using an analogue scale. Variables were compared among treatment groups by use of a 2-factor ANOVA with data categorized into three 10-day treatment periods. A similar comparison was made among treatment groups with data categorized by time of observation (morning, afternoon, or evening) for all study days. RESULTS Variables did not differ among groups at study initiation. Pulse rate was the only variable that differed significantly among treatment groups during the study. During the first 10 days of treatment, dogs receiving PPA had a lower pulse rate than dogs that did not. Although signs of illness were apparent in a few dogs, illness did not appear to be related to treatment. CONCLUSIONS AND CLINICAL RELEVANCE Adverse effects were not detected after administration of selegiline, PPA, or a combination of the drugs in healthy dogs.
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Affiliation(s)
- Leah A Cohn
- Department of Veterinary Medicine and Surgery, College of Veterinary Medicine, University of Missouri, Columbia 65211, USA
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26
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Pelat M, Verwaerde P, Tran MA, Berlan M, Senard JM, Montastruc JL. Changes in vascular alpha 1- and alpha 2-adrenoceptor responsiveness by selegiline treatment. Fundam Clin Pharmacol 2001; 15:239-45. [PMID: 11564130 DOI: 10.1046/j.1472-8206.2001.00036.x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Pharmacoepidemiological studies have reported an excess of mortality with selegiline, a MAO B inhibitor used in the treatment of Parkinson's disease. The mechanism of this putative adverse effect remains unknown but an interaction with the sympathetic nervous system was suggested. The aim of the present study was to investigate the influence of selegiline (10 mg/daily, orally during one week) on vascular alpha1- and alpha2-adrenoceptor responsiveness in conscious unrestrained dogs. Selegiline significantly increased resting values of both systolic and diastolic blood pressures and noradrenaline plasma levels (HPLC) without changing heart rate. Moreover, spectral analysis of systolic blood pressure (Fast Fourier Transformation) showed that selegiline increased the relative energy of a low frequency band without modifying the total spectrum. ED 50 calculated from dose-pressor response curves with phenylephrine (after beta-blockade by propranolol), an index of alpha1-adrenoceptor response or with noradrenaline (after alpha1- and beta blockade by prazosin plus propranolol), an index of alpha2-adrenoceptor response, were significantly higher after selegiline. Selegiline failed to modify the number of platelet alpha2-adrenoceptors measured by [(3)H] RX 821002 binding. Yohimbine-induced increase in noradrenaline release was significantly more marked after selegiline. These results support the evidence that selegiline induces a vascular alpha1- and alpha2-adrenoceptor-hyposensitivity that can be explained by the increase in noradrenaline release elicited by the drug.
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MESH Headings
- Administration, Oral
- Animals
- Blood Pressure/drug effects
- Blood Pressure/physiology
- Dogs
- Dose-Response Relationship, Drug
- Heart Rate/drug effects
- Heart Rate/physiology
- Male
- Monoamine Oxidase Inhibitors/pharmacology
- Muscle, Smooth, Vascular/drug effects
- Muscle, Smooth, Vascular/physiology
- Norepinephrine/blood
- Receptors, Adrenergic, alpha-1/physiology
- Receptors, Adrenergic, alpha-2/physiology
- Selegiline/administration & dosage
- Selegiline/pharmacology
- Yohimbine/administration & dosage
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Affiliation(s)
- M Pelat
- Laboratoire de Pharmacologie Médicale et Clinique, INSERM U 317, Faculté de Médecine, 37 allées Jules-Guesde, BP 72002, 31073 Toulouse Cedex 7, France
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27
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Overall KL. Natural animal models of human psychiatric conditions: assessment of mechanism and validity. Prog Neuropsychopharmacol Biol Psychiatry 2000; 24:727-76. [PMID: 11191711 DOI: 10.1016/s0278-5846(00)00104-4] [Citation(s) in RCA: 141] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
1. The classic animal models for human psychiatric conditions involves rodents. As prey species, their normal behaviors of avoidance would be considered pathological in humans and dogs. Hence, such models may not be homologous for similar behaviors found in psychiatric pathology in humans. 2. Dogs exhibit pathological behavioral conditions that may be equivalent to certain human psychiatric conditions. These canine conditions appear spontaneously or endogenously in the absence of genetic or neurochemcial manipulation, and as such, may be homologous to the human condition. 3. If canine conditions approach homology with human conditions they should have excellent face, predictive, and construct validity. 4. The canine conditions of separation anxiety, obsessive-compulsive disorder, cognitive dysfunction, dominance aggression, and panic disorder have good to excellent validity at all explored levels for human generalized anxiety disorder, obsessive-compulsive disorder, Alzheimer's disease, impulse control disorders, and panic disorder. 5. Natural canine models can aid our understanding of human psychiatric conditions.
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Affiliation(s)
- K L Overall
- Department of Clinical Studies, School of Veterinary Medicine, University of Pennsylvania, Philadelphia 19104-6010, USA
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Abstract
Behavior problems in older pets may be due to many of the same causes as in younger pets. However, the effects of aging on the pet's body may cause a dramatic decline or deterioration in organ and sensory function, which may have a profound impact on the pet's behavior. A decline in cognitive function may also afflict older pets, in many instances due to the occurrence of Alzheimer's disease brain pathology, especially beta amyloid plaque formation. Correlation of geriatric behavior problems, therefore, entails first diagnosing and treating any underlying medical problems. Behavior modification techniques and drug therapy may then be required, with modifications and adjustments made to suit the specific needs of the older pet.
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Affiliation(s)
- G Landsberg
- Doncaster Animal Clinic, Thornhill, Ontario, Canada
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29
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Abstract
Most of the future advances in therapy with behavioral medicine probably will be pharmacologic. Newer developments in tricyclic antidepressants, specific and nonspecific anxiolytics, narcotic agonist-antagonists, and benzodiazepines will have great relevance for veterinary medicine. As the field of behavioral medicine expands, its paradigm hopefully will enlarge to include combination therapy and the implementation of neuropharmacologic intervention as a diagnostic tool. At present, the veterinary practitioner can effectively aid many common behavioral problems, with the glaring exception of most aggressions, using extant drugs.
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Affiliation(s)
- K L Overall
- Department of Clinical Studies, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, USA
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Head E, Hartley J, Kameka AM, Mehta R, Ivy GO, Ruehl WW, Milgram NW. The effects of L-deprenyl on spatial short term memory in young and aged dogs. Prog Neuropsychopharmacol Biol Psychiatry 1996; 20:515-30. [PMID: 8771606 DOI: 10.1016/0278-5846(96)00014-0] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
1. Young and aged dogs were tested on a spatial memory task using a delayed non matching to sample technique. Dogs were tested with 20, 70 and 110 second delay intervals. Animals were pretrained to a stable level of performance prior to treatment. 2. During treatment periods, dogs were orally administered a placebo or I-deprenyl in doses of 0.5 and 1.0 mg/kg in a repeated measures design. 3. Young dogs did not show any significant effects of I-deprenyl, however the sample size was limited. 4. L-deprenyl administration improved spatial memory in aged dogs. 5. The optimal dose or length of treatment time of I-deprenyl varied among individual dogs.
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Affiliation(s)
- E Head
- University of Toronto, Division of Life Sciences, Scarborough, Ontario, Canada
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31
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Yasar S, Goldberg JP, Goldberg SR. Are metabolites of l-deprenyl (selegiline) useful or harmful? Indications from preclinical research. JOURNAL OF NEURAL TRANSMISSION. SUPPLEMENTUM 1996; 48:61-73. [PMID: 8988462 DOI: 10.1007/978-3-7091-7494-4_6] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
A frequent topic of controversy has been whether metabolism of l-deprenyl (selegiline) to active metabolites is a detriment to clinical use. This paper reviews possible roles of the metabolites of l-deprenyl in producing unwanted adverse side effects or in augmenting or mediating its clinically useful actions. Levels of l-amphetamine and l-methamphetamine likely to be reached, even with excessive intake of l-deprenyl, would be unlikely to produce neurotoxicity and there is no preclinical or clinical evidence of abuse liability of l-deprenyl. In contrast, there is evidence that l-amphetamine and l-methamphetamine have some qualitatively different actions than their d-isomer counterparts on EEG and cognitive functioning which might result in beneficial clinical effects and complement beneficial clinical actions of l-deprenyl itself.
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Affiliation(s)
- S Yasar
- Department of Anesthesiology and Critical Care Medicine, Johns Hopkins University, Medical School, Baltimore, MD, USA
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32
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Paterson IA, Davis BA, Durden DA, Juorio AV, Yu PH, Ivy G, Milgram W, Mendonca A, Wu P, Boulton AA. Inhibition of MAO-B by (-)-deprenyl alters dopamine metabolism in the macaque (Macaca facicularis) brain. Neurochem Res 1995; 20:1503-10. [PMID: 8789614 DOI: 10.1007/bf00970600] [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: 02/02/2023]
Abstract
The present study has examined whether MAO-B has a role in DA metabolism in the primate CNS in situ. Eleven macaques (macaca facicularis) were used in this study to examine the effects of (-)-deprenyl (1 mg/kg, i.v., 2 and 24 hours). (-)-Deprenyl administration completely and selectively blocked MAO-B activity and blocked DA metabolism in the caudate nucleus and frontal cortex. DA metabolism in the substantia nigra was not affected by MAO-B inhibition. Changes in DA metabolism were accompanied by changes in 5-hydroxytryptamine (5HT) turnover: 5-hydroxyindole acetic acid (5HIAA) levels increased in the caudate and decreased in the frontal cortex. Levels of 2-phenylethylamine (PE), a putative modulator of dopaminergic transmission, were increased by MAO-B inhibition in all three brain regions examined. It is concluded that in some regions of the primate brain, in contrast to the rat, MAO-B has an important role in DA metabolism.
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Affiliation(s)
- I A Paterson
- Neuropsychiatric Research Unit, University of Saskatchewan, Saskatoon, Canada
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Ruehl WW, Bruyette DS, DePaoli A, Cotman CW, Head E, Milgram NW, Cummings BJ. Canine cognitive dysfunction as a model for human age-related cognitive decline, dementia and Alzheimer's disease: clinical presentation, cognitive testing, pathology and response to 1-deprenyl therapy. PROGRESS IN BRAIN RESEARCH 1995; 106:217-25. [PMID: 8584657 DOI: 10.1016/s0079-6123(08)61218-2] [Citation(s) in RCA: 84] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Affiliation(s)
- W W Ruehl
- Deprenyl Animal Health, Inc., Overland Park, KS 66210, USA
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Murphy MP, Wu PH, Milgram NW, Ivy GO. Monoamine oxidase inhibition by L-deprenyl depends on both sex and route of administration in the rat. Neurochem Res 1993; 18:1299-304. [PMID: 8272194 DOI: 10.1007/bf00975051] [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: 01/29/2023]
Abstract
The monoamine oxidase B (MAO-B) inhibitor L-deprenyl, widely used to treat Parkinson's disease, has frequently been studied in animal models. We have examined the effects of several variables on activity levels of MAO-A and B in rat brain and liver following chronic (3 wks) treatment with L-deprenyl. Significant effects were observed for sex (females showed lower overall MAO-B activity in the liver), dose (MAO-A and B inhibition increased with dose, with females exhibiting greater sensitivity), route of administration (subcutaneous injection was more efficient than oral dosing), and dosing interval (MAO-B was significantly inhibited when dosing interval was increased to as long as 168 hours). Our results thus indicate that the effectiveness of L-deprenyl in vivo is dependent on several factors and that these must be taken into account in studies involving the benefits or risks of this drug.
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Affiliation(s)
- M P Murphy
- Division of Life Sciences, University of Toronto, Scarborough College, Ontario, Canada
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