Biomedical subjects
L Bergström
Publications and source records attributed to L Bergström.
Sulfhydryl reagents have different effects on substance P and neurokinin B binding sites on cortical synaptosomes in the rat.
The effects of several protein modifying reagents, including phenoxybenzamine, N-ethylmaleimide (NEM), 5,5'-dithiobis (2-nitro)--benzoic acid (DTNB), p-chloromercuryphenyl sulfonic acid (PCMP) and p-bromophenacylbromide (PBPB), on the binding of 125I-Bolton Hunter substance P (125I-BHSP), 125I-Bolton Hunter eledoisin (125I-BHELE) and 3H-neurokinin B (3H-NKB)4 to cortical synaptosomes were examined. PCMP (10(-4) M), DTNB (10(-4) M) and NEM (10(-3) M) were without effect on the 125I-BHSP binding but reduced markedly the specific binding of 125I-BHELE or 3H-NKB. Although phenoxybenzamine and PBPB inhibited the 125I-BHSP binding when used in high concentrations (10(-4) M and 10(-3) M), they were more potent in inhibiting the 125I-BHELE or 3H-NKB binding. These results indicate that the NKB binding site is more sensitive to alkylating reagents than the SP binding sites and that these reagents can be used to distinguish SP and NKB receptors in the brain.
Localization of tachykinin binding sites (NK1, NK2, NK3 ligands) in the rat brain.
A comparative autoradiographic analysis of the distribution of tachykinin binding sites was made on brain serial sections using several ligands. (1) 3H-SP, 125I-BHSP and 3H-physalaemin labeled identical binding sites (NK1 type). (2) 3H-NKB, 125I-BHE and 3H-eledoisin also labeled identical sites (NK3 type). (3) 125I-BHNKA preferentially labeled NK3 binding sites, the distribution of 125I-BHNKA binding sites being identical to that of 3H-NKB or 125I-BHE binding sites. (4) The distributions of 3H-SP and 3H-NKB binding sites were markedly different. (5) A very low density of labeling was found with 3H-NKA or 125I-NKA, and these binding sites were distributed only in areas rich in either 3H-SP or 3H-NKB binding sites. (6) Particular efforts were made to look for the presence of tachykinin binding sites in the substantia nigra, since this structure is particularly rich in SP and NKA and contains functional tachykinin receptors of the NK1 and NK2 types as suggested by physiological studies. Confirming previous reports, low or very low labeling was observed in the substantia nigra with 3H-SP or 125I-BHSP and 3H-NKB or 125I-BHE. Similar results were found with 3H-NKA, 125I-NKA or 125I-BHNKA. In conclusion, our data do not provide evidence yet for the existence of NK2 binding sites in the rat brain.
Effects of neonatal handling on nociceptin/orphanin FQ and opioid peptide levels in female rats.
Animals exposed to short periods of handling during the critical period of development, i.e., the first 21 days of life in rats, show attenuated neuroendocrine responses to stress in adult life. We have previously reported long-term changes in brain dynorphin (DYN) peptide levels in male Sprague-Dawley rats after neonatal handling. The purpose of this study was to investigate whether neonatal handling, 15-min individual separation from the mother during postnatal days 1-21, can induce long-term changes in DYNB, Met-enkephalin Arg(6)Phe(7) (MEAP) and nociceptin/orphanin FQ (N/OFQ) immunoreactive (ir) levels in female Sprague-Dawley rats. The peptides were measured in brain and pituitary gland 2 months after the handling procedure. The results reveal that handled (H) rats had increased ir levels of N/OFQ, DYNB and MEAP in the periaqueductal gray (PAG) as compared to nonhandled (NH) controls. Furthermore, H rats had decreased ir levels of DYNB in the frontal cortex and in the amygdala. In contrast to previous findings in male rats, DYNB levels were unaffected in areas related to the hypothalamo-pituitary-adrenal (HPA)-axis. The results indicate that a manipulation early in life can induce persistent neurochemical changes in the N/OFQ and opioid peptide system in female Sprague-Dawley rats.