Neurociencias y aplicaciones psicoterapéuticas en el renacimiento de la investigación con psicodélicos / Neurosciences and psycotherapeutic applications in the psychedelic research renaissaince

The main scope of this review is to expose the main advances regarding recent research of psychedelic substances in the neurociences and their potential psychotherapeutic applications. Psilocybin, a 5-HT2A receptor agonist has been associated with reduced activity in the Default-Mode Network (commonly activated during introspection and self-reflection), enhanced access to biographical memories, positive emotional attentional bias and a reduction on anxiety and mood symptoms. The administration of 3,4-methylenedioxy-N-methylamphetamine (MDMA) could significantly aid the psychotherapeutic process in patients with Post-Traumatic Stress Disorder by strengthening the therapeutic alliance through the release of oxytocin, as well as facilitating emotional regulation from frontal areas to the amygdala during the recollection of traumatic memories. Furthermore, the administration of ayahuasca (an amazonic beverage containing dimethyltryptamine, which binds with the 5-HT2A receptor) and ketamine (a NMDA receptor agonist) in pilot studies has resulted in reduced problematic use of cocaine, heroine, alcohol and tobacco, as well as reported reduction in craving in addiction. While modern research with substances containing psychedelic properties is still young, initial findings suggest the need of expanding the number of studies in order to further clarify their potential risks, benefits and action mechanisms associated to their administration.

El objetivo de esta revisión consiste en exponer los principales avances en la investigación reciente con sustancias psicodélicas en las neurociencias y sus aplicaciones psioterapéuticas. La acción de la psilocibina, un agonista del receptor 5-HT2A, ha sido asociada a una desactivación en la Default Mode Network (activada durante la introspección y pensamientos auto-referentes), un mayor acceso a la memoria autobiográfica, un sesgo atencional emocionalmente positivo y a reducciones en la sintomatología de trastornos de ansiedad y de ánimo. Se ha planteado que la 3,4-metilendioximetanfetamina (MDMA) podría asistir de forma significativa el proceso terapéutico en casos con Trastorno por Estrés Postraumático al fortalecer la alianza terapéutica y permitir una reelaboración de recuerdos traumáticos con menores conductas de evitación. Sus mecanismos terapéuticos se han asociado a la liberación de oxitocina y a una mayor regulación desde áreas frontales hacia la amígdala. Adicionalmente, la administración de ayahuasca (brebaje de origen amazónico que contiene dimetiltriptamina, la cual actúa sobre el receptor 5-HT2A) y ketamina (agonista de receptores NMDA) en estudios iniciales ha resultado en reducción de uso problemático de cocaína, heroína, alcohol, tabaco como también en el "craving" asociado a su consumo. Si bien la investigación moderna de substancias con propiedades psicodélicas es reciente, resultados iniciales fomentan un mayor número de investigaciones para dilucidar los potenciales riesgos, beneficios y mecanismos de acción asociados a su administración.

Aedes albopictus (Diptera: Culicidae): physiological aspects of development and reproduction.

Basic ecophysiological data are presented on the development and reproduction of Aedes albopictus (Skuse) that were reared and maintained at four temperatures between 12 and 32 degrees C. Median larval developmental time from hatching to pupation was correlated inversely with temperature, lasting 7 d at 32 degrees C and up to 28 d at 12 degrees C. Duration of the pupal period also varied from 2-3 d at 32 degrees C to 7-12 d at 12 degrees C. This extension of larval development elongated the phagoperiod and gave rise to larger imagoes. Based on wing length measurements, body sizes varied from 10 to 57 mm3 for females and from 10 to 30 mm3 for males. The caloric protein content at emergence showed a linear and significant regression with body size, independent of sex, treatment, or temperature. Teneral lipid content also followed a linear relationship with body size at warmer temperatures, whereas at low temperatures it increased exponentially with body size. Glycogen was always below 10% of the protein or lipid levels. Reserves at emergence determined median adult survival times, which ranged from 16 d at 32 degrees C to 100 d at 17 degrees C. Access to sucrose solution allowed females to increase their teneral glycogen up to fourfold within 1 wk, and their lipids up to 10-fold within 2 wk. Despite abroad variation, the number of mature oocytes (15-110 eggs per female) was correlated positively with body size, but inversely with the rearing and maintenance temperature. Utilization of the blood meal protein for oogenesis ranged between 35 and 50%, again inversely correlated with temperature; absolute compositions per oocyte were 6.3-6.5 mcal of protein but ranged from 5 to 7 mcal of lipid.

Histone acetylation and disease.

Differential acetylation of histones and transcription factors plays an important regulatory role in developmental processes, proliferation and differentiation. Aberrant acetylation or deacetylation leads to such diverse disorders as leukemia, epithelial cancers, fragile X syndrome and Rubinstein-Taybi syndrome. The various groups of histone acetyltransferases (CBP/p300, GNAT, MYST, nuclear receptor coactivators and TAFII250) and histone deacetylases are surveyed with regard to their possible or known involvement in cancer progression and human developmental disorders. Current treatment strategies are discussed, which are still mostly limited to histone deacetylase inhibitors such as trichostatin A and butyrate.

Aedes aegypti: size, reserves, survival, and flight potential.

Female Aedes aegypti of small and large body sizes were fed ad libitum from eclosion with eight different concentrations of sucrose from 0.1% to 50%; females were also starved with access to water. For each experiment we determined the survivorship of such populations. The 90%, 50%, 10%, and maximal survivorships followed linear regressions with the logarithm of the sucrose concentration. For each condition we measured the extent of synthesis of glycogen and lipid reserves. There was a critical sucrose concentration of 0.5% for both size classes: lower concentrations were of no nutritive effect, and all higher concentrations extended survivorship and allowed reserve synthesis. With respect to the teneral value, and normalized for body size, the maximal amounts of glycogen increased 2-3-fold within one week, whereas lipogenesis increased 3-5-fold requiring two weeks. Solid sugar cubes could also be utilized as long as drinking water was available, but synthesis of additional reserves failed. Flight mill experiments revealed the temporal flight pattern, its maturation after eclosion, and the maximal flight performances. Flights shorter than 1000 m per female per night were considered as low activities, whereas flights lower than 1000 m represented strong vigorous flights. Maximal distances were from 11-18 km/female/night. Periods of continuous flights lasted between 2-9 hr per female (mean 2.2 hr). Maximal flight performances were gradually reached within the first and third day of eclosion. Mean caloric energy consumption during flight was 33% to 44% of the pre-flight glycogen, accompanied by lipid reductions of 9%. Evidently, feeding on carbohydrates allows extended flight activities of this species and is essential for survival in the absence of blood meals.

Larval growth and biosynthesis of reserves in mosquitoes.

Developmental instars of four species of mosquitoes have been analyzed for growth and synthesis of biomass with respect to their caloric content of protein, lipids, and carbohydrates for each instar of Aedes aegypti and Culex pipiens of the subfamily Culicinae, and Anopheles albimanus, and An. gambiae of the subfamily Anophelinae. The diameter of the thorax grows during the intermolt, reflecting continuous increase in biomass because it correlates significantly with the larval synthesis of total protein, lipids, and carbohydrates. For Ae. aegypti the fourth instar was sexed to disclose the sex-specific synthetic potential. In Ae. aegypti the protein increased in linear proportion with larval body size, whereas lipid synthesis followed a significant, exponential regression, which was clearly steeper in male larvae and most pronounced in the last instar. When normalized for size, the size-specific protein and lipid contents showed minimal levels of 0.25 and 0.1, respectively, regardless of standard or crowded rearing conditions. The rate of lipid synthesis in Ae. aegypti was determined by incubating fourth instar larvae with (14)C-acetate and estimating the lipids. The rate was highest in the early larvae and decreased towards the end shortly before pupation; in male larvae incorporation was twice the rate of female larvae. Cx. pipiens reached the largest body sizes of all species tested, with protein and lipids increasing linearly with size. Their minimal levels of size-specific caloric contents were around 0.35 for protein and 0.25 for lipids. Anopheles also showed a linear relationship between larval size and caloric protein and lipid contents. Their minimal threshold levels in size-specific contents were 0.35 for protein and 0.2 for total lipids, similar to Culex, but slightly higher than in Aedes. Starvation of Ae. aegypti larvae and subsequent feeding partially improved their lipid contents, but never to the levels of non-starving, optimal controls. Conversely, well-fed final instars exposed to complete starvation showed a tremendous reduction of the protein and lipids contents in the surviving imagines, accompanied by 73% mortality. These results demonstrate the biosynthetic plasticity and the significance of the phagoperiod in Ae. aegypti during the final fourth instar for growth. The characteristic differences between these two subfamilies in their larval physiology are discussed in relation to ecological factors as encountered in the field under natural conditions, and in relation to our earlier findings on the reproductive physiology.

A comparison of in vivo gene delivery methods for antisense therapy in ligament healing.

To determine the most efficient in vivo delivery method of oligonucleotides for antisense therapy in ligament healing, fluorescence-labelled phosphorothioate oligodeoxynuleotides (ODN) were introduced into 12 rabbit ligament scars 2 weeks after injury using haemagglutinating virus of Japan (Sendai virus: HVJ)-conjugated liposomes. We compared the efficiency of cellular uptake of fluorescence as a percentage of all cells in each scar using three delivery procedures: (1) direct free-hand injection into the ligament scar using a conventional syringe; (2) systematic direct sca injection using a repeating 10 microliters dispenser and a square mesh grid system; and (3) injection into the feeding (femoral) artery. Results showed that there was a significant difference in fluorescence uptake by scar cells on day 1 after injection between the three delivery methods: (1) direct free-hand, 9.7 +/- 7.6% (average +/- s.d.); (2) systematic direct, 58.4 +/- 15.9%; and (3) intra-arterial, 0.2 +/- 0.1%. Systematic direct injection was most efficient and it resulted in 25.9 +/- 13.0% of scar cells being labeled at 7 days after transfection. We then introduced antisense ODN for the rabbit proteoglycan, decorin, into ligament scars with this delivery method and confirmed a significant inhibition of decorin mRNA expression in antisense-treated scar tissues in vivo both at 2 days (42.3 +/- 14.7% of sense control +/- s.d.; P < 0.0025) and 3 weeks (60.5 +/- 28.2% of sense control +/- s.d.; P < 0.024) after treatment, compared with sense ODN-treated scars. Decorin was significantly suppressed also at protein level in antisense-treated scars at 4 weeks (66.6 +/- 35.7% of sense control +/- s.d.; P < 0.045) after treatment. These results demonstrate that in vivo transfection efficiency in ligament scars is 'delivery system dependent' and that introduction of antisense ODN for the small proteoglycan, decorin, with this delivery method can lead to significant suppression of its expression over 3 weeks both at mRNA and protein levels. Thus, an effective model for the potential manipulation of scar composition and quality in ligament healing has been established.

Re-expression of endogenous p16ink4a in oral squamous cell carcinoma lines by 5-aza-2'-deoxycytidine treatment induces a senescence-like state.

We have previously reported that a set of oral squamous cell carcinoma lines express specifically elevated cdk6 activity. One of the cell lines, SCC4, contains a cdk6 amplification and expresses functional p16ink4a, the other cell lines express undetectable levels of p16ink4a, despite a lack of coding-region mutations. Two of the cell lines, SCC15 and SCC40 have a hypermethylated p16ink4A promoter and a third cell line, SCC9, has a mutation in the p16ink4a promoter. Using the demethylation agent 5-aza-2'-deoxycytidine, we showed that the p16ink4a protein was re-expressed after a 5-day treatment with this chemical. One cell line, SCC15 expressed high levels of p16ink4a. In this line, cdk6 activity was decreased after 5-aza-2'deoxycytidine treatment, and the hypophosphorylated, growth suppressive form of the retinoblastoma tumor suppressor protein pRB was detected. Expression of p16ink4a persisted, even after the drug was removed and the cells expressed senescence-associated beta-galactosidase activity. Ectopic expression of p16ink4a with a recombinant retrovirus in this cell line also induced a similar senescence-like phenotype. Hence, it was possible to restore a functional pRB pathway in an oral squamous cell carcinoma line by inducing re-expression of endogenous p16ink4a in response to treatment with a demethylating agent.

Elevated activity of cyclin-dependent kinase 6 in human squamous cell carcinoma lines.

We have investigated the functional integrity of the retinoblastoma tumor suppressor pathway in five human squamous cell carcinoma lines. Elevated activity of cyclin-dependent kinase 6 (cdk6), a pRB kinase, was detected in all five squamous cell carcinoma lines. Overexpression of the cdk6 protein was detected in one of the five cell lines. The cdk6-specific inhibitor p18ink4C is expressed and associated with cdk6 in all five squamous cell carcinoma lines. In contrast, only very low levels of p16ink4A were detected in these cell lines. This may contribute to the elevated activity of cdk6 in these lines. Elevated activity of cdk6 may result in hyperphosphorylation of the retinoblastoma protein and, therefore, compromise its negative growth-regulatory activity.