EFFECTS OF 5HT2 RECEPTOR ANTAGONISTS ON RESPONSES TO POTASSIUM DEPOLARIZATION IN RAT ISOLATED AORTA

1. In order to determine whether 5HT₂ receptor antagonists can modify Ca²⁺ uptake via voltage-operated Ca²⁺ channel (VOC) in arterial smooth muscle, a comparative study of the effects of selected Ca²⁺ uptake blockers and 5HT₂ receptor antagonists on K⁺-induced contractions of rat aortic strip was undertaken. 2. The antagonist drugs studied included the Ca²⁺ uptake blockers verapamil, nifedipine, felodipine, diltiazem and cin-narizine, the 5HT₂ receptor antagonists cyproheptadine, ritanserin, mianserin, and ketanserin and the α₁-adrenoceptor antagonist prazosin. 3. With the notable exception of prazosin, each of these compounds diminished K⁺-induced aortic responses. 4. The following order of potencies (mean IC₅₀ values in mol/L) was established: felodipine (7.0 × 10^-11) >nifedipine (4.8 × 10^-9) >verapamil (5.5 × 10^-8) >cyproheptadine (6.2 × 10^-8) > diltiazem (4.1 × 10^-7) >cinnarizine (1.3 × 10^-6) >ritanserin (1.8 × 10^-6) >ketanserin (9.0 × 10^-6) > mianserin (2.0 × 10^-5). 5. The results suggest that antagonists of 5HT₂ receptors can modulate Ca²⁺ uptake via VOC in rat aorta.     

Predominant usage of the proximal poly(A) site in alpha mRNAs is not intrinsic to the 3' termini

The maturation of IgM-expressing B cells to IgM-secreting plasma cells is associated with both an increase in mu mRNA and the ratio of secreted to membrane forms of mu mRNA. In contrast, previous studies demonstrated that in vitro the secreted form of alpha mRNA (alpha s mRNA) predominates regardless of the stage of B cell differentiation. The present study demonstrates that alpha s mRNA predominates in both B cells derived from the germinal centers of murine Peyer's patches and in the functional IgA memory population, suggesting that in vitro events accurately represent the generation of a secretory IgA response in vivo. Although the predominant usage of the alpha s poly(A) site is due to RNA processing, it does not depend on either the alpha s poly(A) site, the 3' splice site associated with the exon encoding the membrane exon of IgA (alphaM) or the alphaM poly(A) sites. Analysis of the sequence of the intron between the alpha s terminus and alphaM (alpha s- alphaM intron) demonstrates the existence of several potential regulatory elements. Furthermore, the effects of deletions within the alpha s-alphaM intron on 3' terminus usage demonstrate that the predominant usage of the proximal terminus is not strictly dependent on the length of the intron. Together with previous work, these observations support the idea that choice of 3' terminus for all Ig heavy chain genes is regulated by a similar mechanism, but specific sequences within a heavy chain gene can impinge upon that mechanism.      

Psychiatric morbidity in stroke patients attending a neurology clinic in Nigeria

Back ground

Stroke produces a wide range of mental and emotional disorders. Neuropsychiatric complications associated with stroke may have negative effects on the social functioning, overall quality of life and the recovery of motor functioning of stroke survivors.

Objective

To determine the prevalence and nature of psychiatric morbidity among stroke patients attending neurology outpatient clinic of the University of Ilorin Teaching Hospital (UITH), Ilorin-Nigeria.

Methods

All patients with stroke aged 18 years and above at an outpatient neurology clinic in Ilorin, Nigeria were assessed for mental and emotional disorders using the Schedule for Clinical Assessment in Neuropsychiatry (SCAN) over one year (March 2009 to February 2010).

Results

Overall prevalence of psychiatric morbidity was 36.0% (30/83) among 83 patients who constituted the study population. Specific diagnoses recorded were depression (19.2%), generalised anxiety disorder (9.6%), harmful alcohol use (2.4%); dementia, somatoform disorder, phobia and delusional disorder each had a prevalence of 1.2%. Clinical and sociodemographic variables were not significantly associated with psychiatric morbidity.

Conclusion

Psychiatric disorders are often associated with stroke. Identifying and treating stroke patients with these psychiatric co-morbidities could thus help to improve the overall quality of life of these patients.