Effects of ketamine on the cholecystokinin, somatostatin, substance P, and thyrotropin releasing hormone in discrete regions of rat brain

Abstract

Intraperitoneal injection of ketamine (100 mg/kg body weight) significantly reduces the levels of cholecystokinin (CCK), somatostatin (SRIF), and substance P (SP)-like immunoreactivity in various regions of rat brain. No significant change in thyrotropin releasing hormone (TRH)-like immunoreactivity was observed. Neuropeptide systems may be involved in the neuropharmacologic effects of ketamine.

Short-Term Administration of Common Anesthetics Does Not Dramatically Change the Endogenous Peptide Profile in the Rat Pituitary

“…Likewise, short-term exposure to isoflurane has been shown to alter plasma levels of a number of metabolites. , Some studies also suggest that neuropeptide/peptide hormone abundance can be affected by anesthetic treatment. For example, the neuropeptides somatostatin, substance P, and cholecystokinin were found to be altered in several brain regions within 30 min of ketamine injection, while the levels of thyrotropin-releasing hormone did not change during this same time period . Similarly, 15 min isoflurane administration has previously been shown to alter levels of Met-enkephalin and Leu-enkephalin in the brain .…”

“…This contrasts with many prior studies, which examine extended periods of anesthetic administration [24][25][26][29][30][31]65 or measure the changes at time points long after administration (≥30 min). 54,61,64 Our study thus provides valuable insight into any rapid changes in pituitary peptides that may occur in a typical peptidomics study.…”

“…For example, the neuropeptides somatostatin, substance P, and cholecystokinin were found to be altered in several brain regions within 30 min of ketamine injection, while the levels of thyrotropin-releasing hormone did not change during this same time period. 61 Similarly, 15 min isoflurane administration has previously been shown to alter levels of Met-enkephalin and Leu-enkephalin in the brain. 27 Changes in the concentration of cholecystokinin immunoreactivity in the rat brain were noted for anesthetics such as halothane (after 15 min of inhalation), chloral hydrate (30−120 min after injection), and pentobarbital (30−60 min after the injection).…”

“…Second, because our study utilized a nontargeted LC–MS-based approach, we were able to monitor the changes in peptide modifications and degradation that would not be possible with traditional transcriptomic or antibody-based approaches. For example, the peptidomics approach easily allowed for evaluating the relative levels for multiple peptides from a single prohormone, including their individual degradation products, which would not be feasible using commonly used antibody-based approaches like radioimmunoassay. − ,,,,, Finally, we specifically examined peptide changes on a very short time-scale (<5 min total). This contrasts with many prior studies, which examine extended periods of anesthetic administration − ,− , or measure the changes at time points long after administration (≥30 min). ,, Our study thus provides valuable insight into any rapid changes in pituitary peptides that may occur in a typical peptidomics study.…”

Regional changes in neuropeptide levels after 5,7-dihydroxytryptamine-induced serotonin depletion in the rat brain

“…Homogenates were centrifuged at 12,000g for 20min at 4~ and the resulting supernatants were stored at -20 ~ (Pongdohana et al, 1987). The supernatants were dried at room temperature under a continuous N2 gas stream.…”