Abstract
We examined the cellular and subcellular distribution of the cloned κ opioid receptor (KOR1) and its trafficking to the presynaptic plasma membrane in vasopressin magnocellular neurosecretory neurons. We used immunohistochemistry to show that KOR1 immunoreactivity (IR) colocalized with vasopressin-containing cell bodies, axons, and axon terminals within the posterior pituitary. Ultrastructural analysis revealed that a major fraction of KOR1-IR was associated with the membrane of peptide-containing large secretory vesicles. KOR1-IR was rarely associated with the plasma membrane in unstimulated nerve terminals within the posterior pituitary. A physiological stimulus (salt-loading) that elicits vasopressin release also caused KOR1-IR to translocate from these vesicles to the plasma membrane. After stimulation, there was a significant decrease in KOR1-IR associated with peptide- containing vesicles and a significant increase in KOR1-IR associated with the plasma membrane. This stimulus-dependent translocation of receptors to the presynaptic plasma membrane provides a novel mechanism for regulation of transmitter release.
Original language | English (US) |
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Pages (from-to) | 2658-2664 |
Number of pages | 7 |
Journal | Journal of Neuroscience |
Volume | 19 |
Issue number | 7 |
DOIs | |
State | Published - Apr 1 1999 |
Keywords
- Neurosecretory neurons
- Pituitary
- Regulated secretory pathway
- Trafficking
- Translocation
- Vasopressin
- κ opioid receptor