In situ hybridization and immunocytochemistry of alpha(1)-adrenoceptors inhuman peripheral blood lymphocytes

1 alpha (1)-Adrenoceptor subtypes were investigated in cytospin centrifuged preparations of human peripheral blood lymphocytes by in situ hybridizatio n and immunocytochemistry. 2 In situ hybridization cytochemistry revealed alpha (1A)-, alpha (1B)-, an d alpha (1D)-receptor mRNA in human peripheral blood lymphocytes. Lymphocyt es hybridized for alpha (1A) receptor subtype represented approximately 30% of total lymphocytes, those hybridized for alpha (1B)- and alpha (1D)-rece ptor subtypes averaged 42 and 25% of total lymphocytes, respectively. 3 Cytospin centrifuged lymphocytes exposed to anti-alpha (1A)-, alpha (1B)- or alpha (1D)-receptor protein antibodies, developed specific immunostaini ng. Approximately 27% of total lymphocytes were immunoreactive for alpha (1 A)-receptor protein, 40% displayed alpha (1B)-receptor protein immunoreacti vity and 22% alpha (1D)-receptor protein immunoreactivity. Analysis of perc entages as well as of lymphocyte morphology of in situ hybridized and immun olabelled lymphocytes suggests the co-expression of mRNA receptor signal an d protein receptor immunostaining in the same lymphocyte. 4 The demonstration of both alpha (1)-adrenoceptor mRNA and receptor protei n subtypes suggests that alpha (1)-adrenoceptors may have a role in regulat ing lymphocyte function. 5 The possibility of demonstrating receptor protein immunoreactivity in a s mall amount of blood, such as that required for preparing cytospin-centrifu ged lymphocytes, may stimulate research to evaluate the role of these recep tors in lymphocytes and to establish if assessment of lymphocyte alpha (1)- adrenoceptors may represent a marker of their status in health and disease.