L. Grim. University of Wisconsin-Oshkosh.
The The antianxiety effects of antidepressant drugs with pri- extent to which these developmental responses to early-life Chapter 63: Neurobiological Basis of Anxiety Disorders 917 stress may alter the expression of fear and anxiety in adult- global reduction in BZD site binding in seven study subjects hood remains unclear discount forzest 20mg on-line. Anxiety Disorders found no differences in the Bmax order forzest 20 mg on-line, Kd or bound/free values The central BZD receptor has been implicated in anxiety for [11C]flumazenil in any brain region in ten unmedicated disorders on the basis of the anxiolytic and anxiogenic prop- PD study subjects relative to healthy controls (283) discount 20 mg forzest overnight delivery. Hypotheses advanced regarding the role Acute stress increases DA release and turnover in multiple of GABAA-BZD–receptor function in anxiety disorders brain areas purchase 20mg forzest mastercard. The dopaminergic projections to the mPFC have proposed either that changes in the GABAA-BZD mac- appear particularly sensitive to stress buy 20mg forzest with amex, because brief or low- romolecular complex conformation or that alterations in the concentration or properties of an endogenous ligand intensity stressors (e. However, these hypotheses have not been conclu- absence of corresponding changes in other mesotelenceph- sively tested by in vivo or postmortem studies of anxiety- alic dopaminergic projections (284). In con- attacks and increases anticipatory anxiety in some subjects trast, stress of greater intensity or longer duration addition- with PD, but not in healthy controls. In addition, the sensi- ally enhances DA release and metabolism in other areas as tivity to the effects of diazepam on saccadic eye movement well (285). The regional sensitivity to stress appears to fol- velocity is abnormally reduced in PD, a finding implying low a pattern in which dopaminergic projections to the that the functional sensitivity of the GABA -BZD supramo- mPFC are more sensitive to stress than the mesoaccumbens A lecular complex is attenuated in brainstem regions control- and nigrostriatal projections, and the mesoaccumbens dopa- ling saccadic eye movements (275). Subjects with PD also minergic projections are more sensitive to stress than the show abnormally reduced sensitivity to the suppressant ef- nigrostriatal projections (284). Pa- tal (278–280), temporal (278,279), and occipital (278) cor- tients with PD were also shown to have a greater growth tices in subjects with PD relative to control subjects. However, Eriksson absence of medication-free PD study subjects and of healthy et al. A tween CSF HVA and anxiety severity or panic attack fre- SPECT-iomazenil study that quantitated BZD-receptor quency (288). In addition, genetic studies examining associ- binding by derivation of distribution volumes found re- ations between PD and gene polymorphisms for the DA duced binding in the left hippocampus and precuneus in D4 receptor and the DA transporter have produced negative unmedicated PD relative to healthy control samples and results (289). Another ies involving small subject samples reported abnormal re- SPECT-iomazenil study reported lower distribution vol- ductions in DA-receptor binding. These findings appeared social phobic relative to healthy control samples (290), pre- consistent with the evidence cited earlier that stress down- sumably reflecting a reduction in DA-transporter binding. Central BZD-receptor binding has also been assessed in relative to healthy control subjects (291). Conversely, 5-HT2A–receptor expres- nucleus accumbens, amygdala, and lateral hypothalamus in sion is up-regulated during chronic stress and CORT ad- experimental animals (285). During exposure to fear-condi- ministration, and it is down-regulated in response to adre- tioned stimuli, the 5-HT turnover in the mPFC appears nalectomy (298,300). In view of evidence that 5-HT1A and particularly sensitive to the severity of stress, increasing as 5-HT2A receptors may play reciprocal roles in mediating the aversiveness of the US and the magnitude of the condi- anxiety, it is conceivable that these corticosteroid mediated tioned fear behavioral response increases (285). However, effects on 5-HT1A and 5-HT2A expression may be relevant exposure to repeated electric shocks sufficient to produce to the pathophysiology of anxiety. Preadministration of BZD-receptor agonists or tri- The literature regarding serotonergic function in anxiety cyclic antidepressant drugs prevents stress-induced reduc- disorders is in disagreement (see Table 63. In PD, platelet tions in 5-HT release and interferes with the acquisition 5-HT uptake has been reported to be abnormally elevated of learned helplessness, whereas infusion of 5-HT into the (301), normal (302), or abnormally reduced (303). Platelet frontal cortex after stress exposure reverses learned-help- imipramine binding (to a site related to the 5-HT trans- lessness behavior (292,293). Finally, administration of porter site), did not differ in PD relative to control samples 5-HT–receptor antagonists produces behavioral deficits (304,305). Another study reported reduced concentrations resembling those of the learned helplessness seen after ines- of circulating 5-HT in PD relative to control samples (306), capable shock during animal stress models that do not ordi- although this finding has not been replicated. Pharmacologic challenge studies involving 5-HT have The effect of stress in activating 5-HT turnover may been similarly unable to establish a primary role for 5-HT stimulate both anxiogenic and anxiolytic pathways within in the pathophysiology in PD. Neuroendocrine responses the forebrain, depending on the region involved and the to challenge with the 5-HT precursors, L-tryptophan and 5-HT–receptor subtype that is predominantly stimulated. Moreover, appears to enhance conditioned fear, whereas 5-HT injec- tryptophan depletion did not prove anxiogenic in unmedi- tion into the PAG inhibits unconditioned fear (260). Fenfluramine gic innervation of hippocampal 5-HT1A receptors sup- challenge also resulted in reduced CBF in the left posterior presses formation of new CS-US associations and provides parietal-superior temporal cortex in PD study subjects rela- resilience to aversive events. Potentially compatible with this tive to healthy controls (131), although it was unclear hypothesis, 5-HT1A–receptor knockout mice exhibit behav- whether this abnormality reflected an abnormality of seroto- iors consistent with increased anxiety and fear, and long- nergic function or a physiologic correlate of fenfluramine- term administration of 5-HT1A–receptor partial agonists induced anxiety, because more PD study subjects (56%) exerts anxiolytic effects in generalized anxiety disorder developed panic attacks than did control subjects (11%). Preliminary data regarding the sensitivity of specific 5- Notably, stress and glucocorticoids exert major effects HT–receptor subtypes appear more promising, particularly on the genetic expression of 5-HT1A and 5-HT2A receptors. Finally, increases in anxiety and plasma expressed (reviewed in ref. Thus, 5-HT1A–receptor cortisol in PD relative to control samples have been reported density and mRNA levels decrease in response to chronic after oral (312), but not intravenous, administration of stress or CORT administration and increase after adrenalec- the 5-HT2–receptor agonist, m-chloromethylpiperazine tomy (296–299).
Comparison of extrapyrami- robiol Aging 1997;18:S1–S2 discount forzest 20 mg free shipping. J Neurol Neurosurg Psychiatry 1989; Lewy bodies: reliability and validity of clinical and pathologic 52:709–717 discount forzest 20mg with amex. A detailed phenomeno- and sporadic and familial dementia with Lewy bodies forzest 20mg on-line. Neuro- logical comparison of complex visual hallucinations in dementia report 1998;9:3925–3927 discount forzest 20mg without a prescription. Report of the second demen- Ann Neurol 1995;37:110–112 purchase 20mg forzest free shipping. Clin Neuropharmacol 1994;17: tion of diagnostic criteria for dementia with Lewy bodies. Apolipoprotein E epsilon4 disorder and dementia: cognitive differences when compared is associated with neuronal loss in the substantia nigra in Alzhei- with AD. The apolipo- tivities in Lewy body dementia: relation to hallucinosis and protein E epsilon 4 allele increases the risk of drug-induced extrapyramidal features. The CCTTT polymorphism in Neural Transm 1999;106:525–535. Failure to find an associa- muscarinic receptors in dementia of Alzheimer, Parkinson and tion between an intronic polymorphism in the presenilin 1 gene Lewy body types. J Neurol Neurosurg Psychiatry alpha-1 anti-chymotrypsin polymorphism genotyping in Alz- 1999;67:209–213. Butyrylcholinesterase otoxin and nicotine binding in the thalamus. J Neurochem 1999; K: an association with dementia with Lewy bodies. Correlation neuropathology, cholinergic dysfunction and synapse density. What is the neuropathological Neurobiol Aging 1998;19:S207. Striatal dopami- 'prefrontal' and 'limbic' functions. Delayed emergence nergic activities in dementia with Lewy bodies in relation to of a parkinsonian disorder in 38% of 29 older men initially 1314 Neuropsychopharmacology: The Fifth Generation of Progress diagnosed with idiopathic rapid eye movement sleep behavior of the Alzheimer-type and diffuse Lewy body disease. Psychol Med 1999;29: dopaminergic degeneration in dementia with Lewy bodies. Dementia with Lewy atrophy on MRI in dementia with Lewy bodies. Neurology 1999; bodies: a study of post-synaptic dopaminergic receptors with 52:1153–1158. MR-based hippo- of dementia with Lewy bodies: a case series of nine patients. Neuroleptic sensitivity from normal ageing, depression, vascular dementia and other to clozapine in dementia with Lewy bodies. Diagnostico clinico with Lewy bodies: a clinical study. Int J Geriatr Psychiatry 1999; de la demencia asociada a cuerpos de Lewy corticales. Medial temporal type—a review of clinical and pathological features: implica- and whole-brain atrophy in dementia with Lewy bodies: a volu- tions for treatment. Lancet 1996; plications for neurodegenerative disorders. J merous and widespread alpha-synuclein-negative Lewy bodies Neurol Neurosurg Psychiatry 1992;55:1182–1187. Validity of current clinical different types of dementia. Sensitivity and specificity 123I-beta-CIT single-photon emission tomography in dementia of three clinical criteria for dementia with Lewy bodies in an Chapter 91: Dementia with Lewy Bodies 1315 autopsy-verified sample. Int J Geriatr Psychiatry 1999;14: prospective neuropathological validation study. Neurotransmitter systems in diagnostic criteria for the diagnosis of neurodegenerative de- dementia. Validity of clinical pathological and conceptual issues. Eur Arch Psychiatry Clin criteria for the diagnosis of dementia with Lewy bodies.
The major drome generic forzest 20 mg with mastercard, developing within the first 2 years after transplantation 20mg forzest visa. Data differential diagnosis is de novo membranous nephropathy in patients on the incidence of graft failure attributable to membranous disease with a different underlying renal pathology discount forzest 20mg with mastercard. Cyclosporine therapy has made no difference in the branous glomerulonephritis reported in 2% to 5% of transplantations incidence of the two entities cheap forzest 20mg line, and hepatitis C virus infection may be is often asymptomatic and usually associated with chronic rejection associated with membranous disease after transplantation buy 20mg forzest mastercard. FIGURE 17-30 FIGURE 17-31 (see Color Plate) H istologic slide of a biopsy showing extensive spike form ation H istologic slide showing deposition of anti–glom erular basem ent along the glomerular basement membrane. This woman had recurrent m em brane (GBM ) antibody along the GBM , which is seen in over membranous disease 8 months after transplantation. In most of these Both recurrent and de novo m em branous glom erulonephritis are cases no histologic abnormalities are seen within the glomerulus, how- indistinguishable from idiopathic m em branous nephropathy. The ever, and patients remain asymptomatic with normal renal function. Delaying transplantation for at least 6 m onths after antibodies have becom e undetectable reduces the recurrence rate to only 5% to 15%. Treatm ent of the prim ary disease with antibody deposition in anti-GBM disease is diffuse and global and, in plasm a exchange, cyclophospham ide, and steroids leads to rapid practice, is rarely confused with the nonspecific antibody deposition loss of circulating antibodies. Patients who need transplantation seen in other conditions. In chronic transplantation glom erulopathy while circulating antibodies are still detectable should be treated the antibody deposition is focal and segmental, and focal necrosis and with plasm a exchange before and after transplantation to m inim ize cellular crescents are extremely rare. The finding of linear antibody circulating antibody levels and with cyclophospham ide therapy for deposits on a transplantation biopsy should lead to testing for 2 m onths. A sim ilar approach should be used in patients with clini- circulating anti-GBM antibodies. Patients who have linear im m unoglobulin deposi- along with linear IgG staining, m ay be the first indication that a tion in the absence of focal necrosis, crescents, or renal dysfunction patient with an unidentified cause for end-stage renal disease has do not require treatm ent. After transplantation, approxim ately 15% of Chromosome Collagen Diseases caused by mutations patients develop linear deposition of im m unoglobulin G (IgG) along the glom erular basem ent m em brane (GBM ), and circulating 13 1 and 2 chains of type IV anti-GBM antibodies specific for the 3 or 5 chains of type IV 2 3 and 4 chains of type IV Autosomal recessive or dominant collagen [42–44]. Those patients who do develop proteinuria or hem aturia usually lose their grafts. In som e cases, treatm ent with cyclophospham ide did not prevent graft loss. The incidence of H US recurrence is difficult to assess. At one extrem e, five of 11 children suffered graft loss because of recurrent disease. H owever, m ost series have reported substantially lower recurrence rates: no recurrences in 16 adults and children, one of 34 grafts in 28 children, and two probable recurrences of 24 grafts in 20 children [4,45,46]. Graft loss occurs in 10% to 50% of patients with recurrence. HUS has been diagnosed 1 day to 15 months after transplantation (usually in less than 2 months), and the incidence of recurrence is increased in patients receiving grafts less than 3 months after their initial disease. Treatment of recurrent disease is plasma exchange for plasma or cryosupernatant, or plasma infusions, and dose reduction of cyclo- sporine. Recurrence may be prevented by aspirin and dipyridamole. FIGURE 17-36 DIFFERENTIAL DIAGNOSIS OF RECURRENT Blood film abnorm alities, m icroangiopathic hem olytic anem ia, HEM OLYTIC UREM IC SYNDROM E throm bocytopenia, and acute renal failure occur in accelerated hypertension and acute vascular rejection. A renal biopsy usually distinguishes acute vascular rejection, and malignant hypertension Thrombotic microangiopathy associated with cyclosporine should be obvious clinically. The m icroangiopathy of cyclosporine Acute vascular rejection can be difficult to differentiate from hemolytic uremic syndrome; however, glom erular pathology usually is less m arked and vascular Accelerated phase hypertension changes m ore obvious with cyclosporine toxicity. D e novo Tacrolimus- (FK-506) associated thrombotic microangiopathy hem olytic urem ic syndrom e also has been reported in patients treated with tacrolim us (FK-506). Very few patients with system ic sclerosis have received inhibitors after transplantation is unknown. Two of four patients transplantation, and the incidence of acute renal failure caused by with im m unotactoid glom erulopathy developed recurrent disease systemic sclerosis has declined with the widespread use of angiotensin- heralded by m assive proteinuria.
Studies show that the D1-mediated inhibition can act synergistically with D2 stimulation-induced inhibi- calcium currents (79) generic 20 mg forzest fast delivery. In contrast best 20 mg forzest, D2-receptor stimulation tion when the agonists are applied simultaneously generic 20mg forzest fast delivery. How- has been shown to modulate voltage-dependent potassium ever order forzest 20mg on line, the D1-mediated decrease in excitability can be re- conductances in the striatum (80) generic forzest 20 mg on line. This temporal dependence of D1 and stimulation requires the participation of a messenger cascade D2 activation may have functional implications with regard involving the phosphorylation of dopamine- and cAMP- to the tonic/phasic model of DA system regulation (44). In particular, For example, if the DA system exhibits sustained activation this phosphoprotein is a required component in the cascade such as during a reward process, the large phasic DA release mediating D1 function (Fig. Moreover, mice with that results should stimulate both D1 and D2 receptors knockouts of DARPP-32 have been shown to lack D1 mod- located within synapses. In addition, the large DA level ulation of glutamate function, as well as other biochemical released should be sufficient to escape the synaptic cleft, processes and behavioral responses known to involve D1 with the resultant elevated tonic DA levels stimulating the receptors (82). Recent studies have shown that DARPP-32 extrasynaptic D1 receptors (76,77). According to our data, is also present in other, non–D1-containing neurons as well, this should produce synergistic inhibition. On the other including the enkephalin-containing striatal neurons (83). Under this cause a dephosphorylation of DARPP-32 via calcineurin condition, subsequent stimulation of the D2 receptors pref- activation by calcium influx. DARPP-32 is also present in erentially located in the synaptic cleft (78) would be attenu- striatal efferent projection areas, including the globus pal- ated (75). Thus, the system appears to be oriented to provide lidus, entopeduncular nucleus, and substantia nigra (SN) a maximal initial response, whereas continuous activation (83). Thus, DARPP-32 is positioned to exert modulatory would cause an attenuation of subsequent responses. In addition to effects on sodium conductances, D1 stim- ulation also affects high voltage-activated calcium conduc- Modulation of Intercellular Coupling tances. Thus, both D1 agonists and cAMP analogues reduce both N- and P-type calcium currents via a PKA-mediated In addition to its effects on single neurons, DA also is capa- process; however, these manipulations also enhance L-type ble of affecting neuronal interactions on a network level. In 124 Neuropsychopharmacology: The Fifth Generation of Progress particular, substantial evidence has shown DA to have a the DA innervation (i. In all cases, the coupling was present only between The DA system appears to regulate this coupling in two cells of the same morphologic class; that is, between medium ways: (a) acutely, presumably by opening gap junctions that spiny neurons or between aspiny neurons. In addition, with- are already present between neurons in its target structures, drawal from repeated drug treatment such as amphetamine and (b) as a compensatory change in response to a chronic (Fig. Amphetamine and Studies have shown that neurons within the dorsal and antipsychotic drugs increase coupling in limbic striatum, ventral striatum exhibit dye coupling, which is the morpho- whereas classic antipsychotic drugs also cause an increase in logic correlate of gap junctions between neurons. In striatal coupling in the motor-related dorsal striatum. These effects slices recorded in vitro, application of the D2 agonist quin- are only observed following withdrawal from the drug. D1 agonists, in contrast, do not possible that the system compensates for the presence of affect coupling in a measurable way; however, in brain slices the drug by altering gap junctions to allow coupling to be derived from a DARPP-32 knockout rat, the basal level of maintained at its basal state. Under these conditions, the coupling is significantly higher than in control, and further- alteration is only observed when the adapted state is altered more, the D2 agonist fails to increase coupling above this by withdrawal of the drug. Indeed, the observation that elevated baseline (75). These data suggest that coupling is coupling is maintained for weeks following drug withdrawal suggests that the system may have reached a new stable normally suppressed by an action of DARPP-32, and that steady state that could leave it more susceptible to destabiliz- this suppression can be overcome by D2 agonist administra- ing influences (85). Dye coupling is also affected by maintained changes in Interactions with Other Neurotransmitters DA system function. Changes in coupling are observed fol- lowing lesions of the DA system with the neurotoxin 6- DA has also been shown to affect the response of striatal hydroxydopamine. Only the rats that exhibit severe loss of neurons to other neurotransmitters. Long-term alterations in DA transmission lead to changes in dye coupling within the striatal complex. Medium spiny neurons in the nucleus accumbens were injected during in vivo intracellular recording with Lucifer yellow, which was then converted into a dense stain using antibodies. In a control rat, injection of Lucifer yellow typically labels only a single neuron (left); overall, less than 15% of accumbens neurons injected in control rats exhibit labeling of more than a single neuron. In contrast, in rats that had been administered amphetamine for 2 to 4 weeks and then withdrawn for at least 7 days, the majority of injected neurons exhibited dye coupling ( 60% of cells injected).
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