RESUMO
The end of the millennium provides an opportunity to review some of the common practices that were present in psychopharmacology during the 20th century. The author focuses on two approaches that have dominated research and guided the clinical application of psychopharmacologic therapeutics: the unitary clinically-based and single-lesion perspectives. The author expands upon these older formulations of neuropsychiatric disease pathogenesis and describes how the approach to psychopharmacologic research and therapeutics has changed in light of advances in the basic neurosciences. Relevant recent advances in the basic neurosciences that shed light on the pathophysiology of neuropsychiatric disease states and that guide psychopharmacologic practices are described. The use of atypical antipsychotic agents to treat schizophrenia is given as one example of the clinical applications of the approach to psychopharmacology in the next century.
RESUMO
In this study we describe the identification of four soluble forms of cyclic nucleotide phosphodiesterase from chicken gizzard smooth muscle. These isoenzymes were separated from one another by ion-exchange chromatography on DEAE-cellulose and by calmodulin-Sepharose affinity chromatography. Each form migrates as a single discrete band when it is electrophoresed on non-denaturing polyacrylamide gels and stained for phosphodiesterase activity. Each form is also eluted as a single peak on gel-permeation chromatography, giving apparent Mr values of 114 000, 116 000, 122 000 and 59 000. All four enzymes have apparent Km values in the 0-20 microM range, although their relative specificities for cyclic AMP and cyclic GMP differ. Two of the forms bind to calmodulin in a Ca2+-dependent manner; however, only one is activated by calmodulin. The interaction of the second calmodulin-binding form with calmodulin is disrupted by the papaverine derivative verapamil without significantly altering the hydrolytic activity of the enzyme.
