Educating pharmacy students through a pandemic: Reflecting on our COVID-19 experience.

The impact of the COVID-19 pandemic on pharmacy education worldwide has been immense, affecting students, educators and regulatory agencies. Pharmacy programmes have had to rapidly adapt in their delivery of education, maintaining standards while also ensuring the safety of all stakeholders. In this commentary, we describe the challenges, compromises and solutions adopted by our institution throughout the pandemic, the lessons learnt, adaptive measures taken, and strategies to develop and future-proof our curricula.

Ethologically based behavioural and neurochemical characterisation of mice with isoform-specific loss of dysbindin-1A in the context of schizophrenia.

Dysbindin-1 is implicated in several aspects of schizophrenia, including cognition and both glutamatergic and dopaminergic neurotransmission. Targeted knockout of dysbindin-1A (Dys-1A KO), the most abundant and widely expressed isoform in the brain, is associated with deficits in delay/interference-dependent working memory. Using an ethologically based approach, the following behavioural phenotypes were examined in Dys-1A KO mice: exploratory activity, social interaction, anxiety and problem-solving ability. Levels of monoamines and their metabolites were measured in striatum, hippocampus and prefrontal cortex using high-performance liquid chromatography with electrochemical detection. The ethogram of initial exploration in Dys-1A KO mice was characterised by increased rearing from a seated position; over subsequent habituation, stillness was decreased relative to wildtype. In a test of dyadic social interaction with an unfamiliar conspecific in a novel environment, female KO mice showed an increase in investigative social behaviours. Marble burying behaviour was unchanged. Using the puzzle-box test to measure general problem-solving performance, no effect of genotype was observed across nine trials of increasing complexity. Dys-1A KO demonstrated lower levels of 5-HT in ratio to its metabolite 5-HIAA in the prefrontal cortex. These studies elaborate the behavioural and neurochemical phenotype of Dys-1A KO mice, revealing subtle genotype-related differences in non-social and social exploratory behaviours and habituation of exploration in a novel environment, as well as changes in 5-HT activity in brain areas related to schizophrenia.

Acute stress in adolescence vs early adulthood following selective deletion of dysbindin-1A: Effects on anxiety, cognition and other schizophrenia-related phenotypes.

BACKGROUND: As exposure to stress has been linked to the onset and maintenance of psychotic illness, its pathogenesis may involve environmental stressors interacting with genetic vulnerability. AIM: To establish whether acute stress interacts with a targeted mutation of the gene encoding the neurodevelopmental factor dystrobrevin-binding protein 1 (DTNBP1), resulting in a specific loss of the isoform dysbindin-1A, to influence schizophrenia-relevant phenotypes in mice during adolescence and adulthood. METHODS: Male and female mice with a heterozygous or homozygous deletion of DTNBP1 were assessed in the open field test following acute restraint stress in adolescence (Day 35) and young adulthood (Day 60-70). Effects of acute restraint stress on memory retention in the novel object recognition test was also assessed in adulthood. Baseline corticosterone was measured in serum samples and, brain-derived neurotrophic factor (BDNF), glucocorticoid and mineralocorticoid receptor gene expression levels were measured in the hippocampus of adult mice. RESULTS: In the open field, deletion of dysbindin-1A induced hyperactivity and attenuated the action of stress to reduce hyperactivity in adolescence but not in adulthood; in females deletion of dysbindin-1A attenuated the effect of acute stress to increase anxiety-related behaviour in adolescence but not in adulthood. In the novel object recognition test, deletion of dysbindin-1A impaired memory and also revealed an increase in anxiety-related behaviour and a decrease in hippocampal BDNF gene expression in males. CONCLUSIONS: These data suggest that deletion of dysbindin-1A influences behaviours related to schizophrenia and anxiety more robustly in adolescence than in adulthood and that dysbindin-1A influences stress-related responses in a sex-dependent manner.

Dysregulation of Specialized Delay/Interference-Dependent Working Memory Following Loss of Dysbindin-1A in Schizophrenia-Related Phenotypes.

Dysbindin-1, a protein that regulates aspects of early and late brain development, has been implicated in the pathobiology of schizophrenia. As the functional roles of the three major isoforms of dysbindin-1, (A, B, and C) remain unknown, we generated a novel mutant mouse, dys-1A-/-, with selective loss of dysbindin-1A and investigated schizophrenia-related phenotypes in both males and females. Loss of dysbindin-1A resulted in heightened initial exploration and disruption in subsequent habituation to a novel environment, together with heightened anxiety-related behavior in a stressful environment. Loss of dysbindin-1A was not associated with disruption of either long-term (olfactory) memory or spontaneous alternation behavior. However, dys-1A-/- showed enhancement in delay-dependent working memory under high levels of interference relative to controls, ie, impairment in sensitivity to the disruptive effect of such interference. These findings in dys-1A-/- provide the first evidence for differential functional roles for dysbindin-1A vs dysbindin-1C isoforms among phenotypes relevant to the pathobiology of schizophrenia. Future studies should investigate putative sex differences in these phenotypic effects.

Altered cytokine profile, pain sensitivity, and stress responsivity in mice with co-disruption of the developmental genes Neuregulin-1×DISC1.

The complex genetic origins of many human disorders suggest that epistatic (gene×gene) interactions may contribute to a significant proportion of their heritability estimates and phenotypic heterogeneity. Simultaneous disruption of the developmental genes and schizophrenia risk factors Neuregulin-1 (NRG1) and Disrupted-in-schizophrenia 1 (DISC1) in mice has been shown to produce disease-relevant and domain-specific phenotypic profiles different from that observed following disruption of either gene alone. In the current study, anxiety and stress responsivity phenotypes in male and female mutant mice with simultaneous disruption of DISC1 and NRG1 were examined. NRG1×DISC1 mutant mice were generated and adult mice from each genotype were assessed for pain sensitivity (hot plate and tail flick tests), anxiety (light-dark box), and stress-induced hypothermia. Serum samples were assayed to measure circulating levels of pro-inflammatory cytokines. Mice with the NRG1 mutation, irrespective of DISC1 mutation, spent significantly more time in the light chamber, displayed increased core body temperature following acute stress, and decreased pain sensitivity. Basal serum levels of cytokines IL8, IL1ß and IL10 were decreased in NRG1 mutants. Mutation of DISC1, in the absence of epistatic interaction with NRG1, was associated with increased serum levels of IL1ß. Epistatic effects were evident for IL6, IL12 and TNFα. NRG1 mutation alters stress and pain responsivity, anxiety, and is associated with changes in basal cytokine levels. Epistasis resulting from synergistic NRG1 and DISC1 gene mutations altered pro-inflammatory cytokine levels relative to the effects of each of these genes individually, highlighting the importance of epistatic mechanisms in immune-related pathology.

Epistatic and Independent Effects on Schizophrenia-Related Phenotypes Following Co-disruption of the Risk Factors Neuregulin-1 × DISC1.

Few studies have addressed likely gene × gene (ie, epistatic) interactions in mediating risk for schizophrenia. Using a preclinical genetic approach, we investigated whether simultaneous disruption of the risk factors Neuregulin-1 (NRG1) and Disrupted-in-schizophrenia 1 (DISC1) would produce a disease-relevant phenotypic profile different from that observed following disruption to either gene alone. NRG1 heterozygotes exhibited hyperactivity and disruption to prepulse inhibition, both reversed by antipsychotic treatment, and accompanied by reduced striatal dopamine D2 receptor protein expression, impaired social cognition, and altered glutamatergic synaptic protein expression in selected brain areas. Single gene DISC1 mutants demonstrated a disruption in social cognition and nest-building, altered brain 5-hydroxytryptamine levels and hippocampal ErbB4 expression, and decreased cortical expression of the schizophrenia-associated microRNA miR-29b. Co-disruption of DISC1 and NRG1, indicative of epistasis, evoked an impairment in sociability and enhanced self-grooming, accompanied by changes in hypothalamic oxytocin/vasopressin gene expression. The findings indicate specific behavioral correlates and underlying cellular pathways downstream of main effects of DNA variation in the schizophrenia-associated genes NRG1 and DISC1.

Phenotypic effects of repeated psychosocial stress during adolescence in mice mutant for the schizophrenia risk gene neuregulin-1: a putative model of gene × environment interaction.

There is a paucity of animal models by which the contributions of environmental and genetic factors to the pathobiology of psychosis can be investigated. This study examined the individual and combined effects of chronic social stress during adolescence and deletion of the schizophrenia risk gene neuregulin-1 (NRG1) on adult mouse phenotype. Mice were exposed to repeated social defeat stress during adolescence and assessed for exploratory behaviour, working memory, sucrose preference, social behaviour and prepulse inhibition in adulthood. Thereafter, in vitro cytokine responses to mitogen stimulation and corticosterone inhibition were assayed in spleen cells, with measurement of cytokine and brain-derived neurotrophic factor (BDNF) mRNA in frontal cortex, hippocampus and striatum. NRG1 mutants exhibited hyperactivity, decreased anxiety, impaired sensorimotor gating and reduced preference for social novelty. The effects of stress on exploratory/anxiety-related parameters, spatial working memory, sucrose preference and basal cytokine levels were modified by NRG1 deletion. Stress also exerted varied effect on spleen cytokine response to concanavalin A and brain cytokine and BDNF mRNA expression in NRG1 mutants. The experience of psychosocial stress during adolescence may trigger further pathobiological features that contribute to the development of schizophrenia, particularly in those with underlying NRG1 gene abnormalities. This model elaborates the importance of gene × environment interactions in the etiology of schizophrenia.

Genetic vs. pharmacological inactivation of COMT influences cannabinoid-induced expression of schizophrenia-related phenotypes.

Catechol-O-methyltransferase (COMT) is an important enzyme in the metabolism of dopamine and disturbance in dopamine function is proposed to be central to the pathogenesis of schizophrenia. Clinical epidemiological studies have indicated cannabis use to confer a 2-fold increase in risk for subsequent onset of psychosis, with adolescent-onset use conveying even higher risk. There is evidence that a high activity COMT polymorphism moderates the effects of adolescent exposure to cannabis on risk for adult psychosis. In this paper we compared the effect of chronic adolescent exposure to the cannabinoid WIN 55212 on sensorimotor gating, behaviours related to the negative symptoms of schizophrenia, anxiety- and stress-related behaviours, as well as ex-vivo brain dopamine and serotonin levels, in COMT KO vs. wild-type (WT) mice. Additionally, we examined the effect of pretreatment with the COMT inhibitor tolcapone on acute effects of this cannabinoid on sensorimotor gating in C57BL/6 mice. COMT KO mice were shown to be more vulnerable than WT to the disruptive effects of adolescent cannabinoid treatment on prepulse inhibition (PPI). Acute pharmacological inhibition of COMT in C57BL/6 mice also modified acute cannabinoid effects on startle reactivity, as well as PPI, indicating that chronic and acute loss of COMT can produce dissociable effects on the behavioural effects of cannabinoids. COMT KO mice also demonstrated differential effects of adolescent cannabinoid administration on sociability and anxiety-related behaviour, both confirming and extending earlier reports of COMT×cannabinoid effects on the expression of schizophrenia-related endophenotypes.

Physiological and behavioural responsivity to stress and anxiogenic stimuli in COMT-deficient mice.

Catechol-O-methyltransferase, an enzyme involved in regulating brain catecholamine levels, has been implicated in anxiety, pain and/or stress responsivity. Elements of this putative association remain unclarified, notably whether: (a) COMT variation modulates responses to acute and/or chronic stress equally; (b) acute pharmacological inhibition of COMT produces comparable effects on anxiety to that observed after deletion of the COMT gene; (c) COMT genotype modulates action of anxiolytic drugs. We aimed to further investigate the relationship between reduced COMT function, anxiety and stress responsivity in mice. To compare the effect of acute vs. chronic restraint stress in female COMT KO vs. WT mice, serum corticosterone and cytokine concentrations were measured [Experiment 1]. Sensitivity to the benzodiazepines midazolam and chlordiazepoxide in the light-dark test was assessed in female COMT KO vs. WT mice [Experiment 2]. Effects of acute administration of the COMT inhibitor tolcapone, and of these same benzodiazepines thereon, in the light-dark test were assessed in female C57BL/6 mice [Experiment 3]. COMT KO mice demonstrated an increased corticosterone response to acute but not chronic stress, and a modified cytokine profile after chronic, but not acute stress. COMT KO mice showed increased anxiety, but benzodiazepine sensitivity was affected by COMT genotype. Whilst tolcapone had no effect on light/dark performance in C57BL6/J mice it decreased benzodiazepine sensitivity. These data elaborate earlier findings of increased anxiety in female COMT KO mice and also clarify a role for COMT in modulating stress-related hormonal and immune parameters in a manner that depends on chronicity of the stressor.

Chronic adolescent exposure to Δ-9-tetrahydrocannabinol in COMT mutant mice: impact on psychosis-related and other phenotypes.

Cannabis use confers a two-fold increase in the risk for psychosis, with adolescent use conferring even greater risk. A high-low activity catechol-O-methyltransferase (COMT) polymorphism may modulate the effects of adolescent Δ-9-tetrahydrocannabinol (THC) exposure on the risk for adult psychosis. Mice with knockout of the COMT gene were treated chronically with THC (4.0 and 8.0 mg/kg over 20 days) during either adolescence (postnatal days (PDs) 32-52) or adulthood (PDs 70-90). The effects of THC exposure were then assessed in adulthood across behavioral phenotypes relevant for psychosis: exploratory activity, spatial working memory (spontaneous and delayed alternation), object recognition memory, social interaction (sociability and social novelty preference), and anxiety (elevated plus maze). Adolescent THC administration induced a larger increase in exploratory activity, greater impairment in spatial working memory, and a stronger anti-anxiety effect in COMT knockouts than in wild types, primarily among males. No such effects of selective adolescent THC administration were evident for other behaviors. Both object recognition memory and social novelty preference were disrupted by either adolescent or adult THC administration, independent of genotype. The COMT genotype exerts specific modulation of responsivity to chronic THC administration during adolescence in terms of exploratory activity, spatial working memory, and anxiety. These findings illuminate the interaction between genes and adverse environmental exposures over a particular stage of development in the expression of the psychosis phenotype.

Confirmation that the renin gene distal enhancer polymorphism REN-5312C/T is associated with increased blood pressure.

BACKGROUND: Studies of knockout and transgenic mice have demonstrated key roles for genes encoding components of the renin angiotensin system in blood pressure regulation. However, whether polymorphisms in these genes contribute to the cause of essential hypertension in humans is still a matter of debate. METHODS AND RESULTS: We performed an experiment with dense tagging single-nucleotide polymorphism coverage of 4 genes encoding proteins that control the overall activity of the cascade, namely renin, angiotensinogen, angiotensin-converting enzyme, and angiotensin-converting enzyme 2, in 2 Irish populations. Both clinic and 24-hour ambulatory blood pressure measurements were available from population I (n=387), whereas just clinic blood pressure was measured in population II (n=1024). Of the 23 polymorphisms genotyped, only a single renin gene polymorphism, REN-5312C/T, showed consistent statistically significant associations with elevated diastolic pressures. Carriage of one REN-5312T allele was associated with the following age- and sex-adjusted increments in diastolic pressures (mean [95% CI]): population I, clinic, 1.5 mm Hg (0.3 to 2.8); daytime, 1.4 mm Hg (0.4 to 2.4); night-time, 1.3 mm Hg (0.4 to 2.3), and population II, clinic, 1.1 mm Hg (0.1 to 2.1). Haplotypic analyses and multivariate stepwise regression analyses were in concordance with individual single-nucleotide polymorphism analyses. CONCLUSIONS: The REN-5312T allele had been shown previously to result in increased in vitro expression of the renin gene. We have now shown, in 2 independent populations, that carriage of a REN-5312T allele is associated with elevated diastolic blood pressure. These data provide evidence that renin is an important susceptibility gene for arterial hypertension in whites.

Phenotype of spontaneous orofacial dyskinesia in neuregulin-1 'knockout' mice.

Studies in antipsychotic-naïve patients with schizophrenia indicate a baseline level of spontaneous involuntary movements, particularly orofacial dyskinesia. Neuregulin-1 is associated with risk for schizophrenia and its functional role can be studied in 'knockout' mice. We have shown previously that neuregulin-1 'knockouts' evidence disruption in social behaviour. Neuregulin-1 'knockouts' were assessed for four topographies of orofacial movement, both spontaneously and under challenge with the D(1)-like dopamine receptor agonist SKF 83959. Neuregulin-1 'knockouts' evidenced an increase in spontaneous incisor chattering, particularly among males. SKF 83959 induced incisor chattering, vertical jaw movements and tongue protrusions; the level of horizontal jaw movements was increased and that of tongue protrusions decreased in neuregulin-1 'knockouts'. These findings indicate that the schizophrenia risk gene neuregulin-1 is involved in the regulation of not only social behaviour but also orofacial dyskinesia. Orofacial dyskinesia in neuregulin-1 mutants may indicate some modest genetic relationship between risk for schizophrenia and vulnerability to spontaneous movement disorder.

Exploratory and habituation phenotype of heterozygous and homozygous COMT knockout mice.

Catechol-O-methyltransferase (COMT) inactivates dopamine in prefrontal cortex and is associated clinically with a schizophrenia endophenotype. Using an ethologically based approach, the phenotype of mice with heterozygous COMT deletion was characterised by decreased rearing with increased sifting and chewing. Heterozygous COMT deletion is associated with a distinctive phenotype. This differs from that which we have reported previously for heterozygous deletion of the schizophrenia risk gene neuregulin-1.

Disruption of orofacial movement topographies in congenic mutants with dopamine D5 but not D4 receptor or DARPP-32 transduction 'knockout'.

The role of D(1)-like [D(1), D(5)] and D(2)-like [D(2), D(3), D(4)] dopamine receptors and dopamine transduction via DARPP-32 in topographies of orofacial movement was assessed in restrained mice with congenic D(4) vs. D(5) receptor vs. DARPP-32 'knockout'. D(4) and DARPP-32 mutants evidenced no material phenotype; also, there were no alterations in topographical responsivity to either the selective D(2)-like agonist RU 24213 or the selective D(1)-like agonist SK and F 83959. In contrast, D(5) mutants evidenced an increase in spontaneous vertical jaw movements, which habituated more slowly than in wildtypes, and a decrease in horizontal jaw movements; topographical responsivity to SK and F 83959 and RU 24213 was unaltered. D(5) receptors regulate distinct topographies of vertical and horizontal jaw movement in an opposite manner. In assuming that the well-recognised role of the D(1)-like family in regulating orofacial movements involves primarily D(1) receptors, a role for their D(5) counterparts may have been overlooked.

Ethological resolution of behavioral topography and D2-like vs. D1-like agonist responses in congenic D4 dopamine receptor "knockouts": identification of D4:D1-like interactions.

To clarify the involvement of dopamine D4 receptors in behavioral regulation, the phenotypic ethogram of congenic D4 "knockout" mice was studied in terms of (i) course of exploration and habituation, and (ii) topographical responsiveness to the selective D2-like agonist RU 24213 and the selective D1-like agonists A 68930, SK&F 83959 and SK&F 83822. Congenic D4 knockouts were characterized by a small reduction in exploratory sniffing with delayed habituation of sifting. The magnitude and topographical specificity of these effects indicated that any functional role for D4 receptors in exploratory processes is subtle. Induction of stereotyped, ponderous locomotion by RU 24213 was reduced in D4-null mice consistent with an involvement of D4 receptors in the topographical expression of stereotypy. Induction of grooming and, at higher doses, seizures by A 68930, which stimulates both adenylyl cyclase (AC) and phospholipase C (PLC), were unaltered in congenic D4 knockouts. In contrast, induction of grooming by SK&F 83959, which stimulates PLC but not AC and fails to induce seizures, was reduced in D4-null mice; this indicates that D4 receptors interact with PLC-coupled D1-like receptors in regulating D1-like-mediated grooming. Conversely, induction of seizures by SK&F 83822, which stimulates AC but not PLC and fails to induce grooming, was reduced in congenic D4 knockouts; this indicates that D4 receptors interact with AC-coupled D1-like receptors in regulating D1-like-mediated seizures. These studies identify novel functional roles for the D4 receptor that are distinct from those of closely related D2-like family members and involve interactions with their D1-like counterparts.

Sexually dimorphic changes in the exploratory and habituation profiles of heterozygous neuregulin-1 knockout mice.

The neuregulin-1 gene is widely expressed in the central nervous system and is associated with increased risk for schizophrenia. Using an ethologically based approach, the phenotype of neuregulin-1 heterozygous knockout mice was examined by revealing the individual elements of behaviour in the murine repertoire over the prolonged course of interaction with the environment. During initial exploration, neuregulin-1 mutants displayed a phenotype characterized by increases in locomotion and rearing free, with sex-specific alterations in sifting and grooming. Over subsequent habituation, certain initial effects endured while new phenotypic effects emerged, some of which were again sex-specific. These studies elaborate a pleiotropic role of neuregulin-1 in development, plasticity and function, including sexual dimorphism, by defining the elemental, temporal and sex-specific characteristics of the neuregulin-1 mutant ethogram.

Ethological resolution of behavioural topography and D1-like versus D2-like agonist responses in congenic D5 dopamine receptor mutants: identification of D5:D2-like interactions.

The phenotypic ethogram of congenic dopamine D(5) receptor "knockout" mice was evaluated. Each individual topography of behaviour within the natural repertoire was assessed over the extended course of initial exploration of and subsequent habituation to the environment, and following challenge with a series of D(1)-like agonists. Over initial exploration, D(5)-null mice evidenced a modest reduction in locomotion and a modest increase in sifting. Subsequent habituation revealed additional phenotypic effects, primarily overall reduction in grooming and delayed habituation of rearing. Among D(1)-like agonists, A 68930 stimulates both adenylyl cyclase and a putative D(1)-like receptor coupled to stimulation of phospholipase C-mediated phosphoinositide hydrolysis; conversely, SK&F 83959 stimulates phosphoinositide hydrolysis but not adenylyl cyclase while SK&F 83822 stimulates adenylyl cyclase but not phosphoinositide hydrolysis. Though programmed grooming syntax and episodic seizure activity induced by A 68930 and SK&F 83822 were unaltered, grooming induced by SK&F 83959 was reduced in D(5) mutants. Stereotyped, ponderous locomotion induced by the D(2)-like agonist RU 24213 was enhanced in D(5) mutants. Phenotypic and pharmacological characterisation of congenic D(5)-null mice at an ethological level identifies novel functional roles for the D(5) receptor in mediating discrete topographies of behaviour relating to exploration, sequential motor coordination, and how these processes change over the course of interaction with and habituation to the environment. Additionally, they indicate the involvement of phosphoinositide hydrolysis and D(5):D(2)-like interactions in regulating these processes.

Frequency distribution of the Los Angeles and Duarte galactose-1-phosphate uridyltransferase variant alleles in the Irish population.

Anonymous population screening was carried out to detect the N314D, Los Angeles (D1), and Duarte (D2) alleles of the galactose-1-phosphate uridyltransferase gene in Ireland using 743 blood samples, covering the Traveller (n = 243) and non-Traveller (n = 500) population groups. The frequency of the N314D substitution was found to be 0.099 overall. D1 allele frequencies were found to be 0.031 and 0.023 in the Traveller and non-Traveller groups, respectively, while D2 allele frequencies were 0.058 and 0.076, respectively. No significant differences in allele frequency were detected between the Traveller and non-Traveller groups, or between the Irish population groups and the literature values for Northern and Western Europe.

Ethologically based resolution of D2-like dopamine receptor agonist-versus antagonist-induced behavioral topography in dopamine- and adenosine 3',5'-monophosphate-regulated phosphoprotein of 32 kDa "knockout" mutants congenic on the C57BL/6 genetic background.

Given the critical role of dopamine- and adenosine 3',5'-monophosphate-regulated phosphoprotein of 32 kDa (DARPP-32) in the regulation of dopaminergic function, DARPP-32-null mutant mice congenic on the inbred C57BL/6 strain for 10 generations were examined phenotypically for their ethogram of responsivity to the selective D2-like receptor agonist RU 24213 (N-n-propyl-N-phenylethyl-p-3-hydroxyphenylethylamine) and the selective D2-like receptor antagonist YM 09151-2 (cis-N-[1-benzyl-2-methyl-pyrrolidin-3-yl]-5-chloro-2-methoxy-4-methylaminobenzamide), using procedures that resolve all topographies of behavior in the natural repertoire. After vehicle challenge, levels of sniffing and rearing seated were reduced in DARPP-32 mutants; the injection procedure seems to constitute a "stressor" that reveals phenotypic effects of DARPP-32 deletion not apparent under natural conditions. Topographical effects of 0.3 to 10.0 mg/kg RU 24213, primarily induction of sniffing and ponderous locomotion with accompanying reductions in rearing, grooming, sifting and chewing, were not altered to any material extent in DARPP-32-null mice. However, topographical effects of 0.005 to 0.625 mg/kg YM 09151-2, namely, reduction in sniffing, locomotion, rearing, grooming, and chewing but not sifting, were essentially absent in DARPP-32 mutants. Thus, the D2-like receptor agonist-mediated ethogram was essentially conserved, whereas major elements of the corresponding D2-like receptor antagonist-mediated ethogram were essentially absent in DARPP-32-null mice. This suggests some relationship between 1) extent of tonic dopaminergic activation of DARPP-32 mechanisms and 2) compensatory mechanisms consequent to the developmental absence of DARPP-32, which may emerge to act differentially on individual elements of the DARPP-32 system. Critically, the present data indicate that phenotypic effects of a given gene deletion using an agonist acting on the system disrupted cannot be generalized to a corresponding antagonist, and vice versa.

Identification of sequence variation in the galactose-1-phosphate uridyl transferase gene by dHPLC.

Transferase-deficient galactosaemia is an inherited disorder of carbohydrate metabolism, caused by mutation at the galactose-1-phosphate uridyl transferase (GALT) locus. A denaturing high performance liquid chromatography (dHPLC) method was developed for variant scanning of the GALT gene. The method unequivocally identified the Duarte D1, D2, Q188R, and K285N GALT alleles and associated polymorphisms. Length polymorphism in an intronic Alu repeat was characterised and a novel Single Nucleotide Polymorphism (IVS10nt-322g-->t) associated with the D1 allele was identified.