Prolyl-leucyl-glycinamide (PLG); regional effects on α-MPT-induced catecholamine disappearance in rat brain

Content Provider	Semantic Scholar
Author	Versteeg, Dirk H. G. Tanaka, Masatoshi Kloet, Edo Ronald De Ree, Jan M. Van Wied, David De
Copyright Year	1978
Abstract	Previously, we have reported that arginineS-vasopressin (AVP), a peptide which exerts marked effects on learning and memory processes (for a review see ref. 4), affects a-MPT-induced catecholamine disappearance in regions of the rat brain which specifically have been implicated in such processes21, ez. Recently, it has been shown that prolyl-leucyl-glycinamide (PLG), which is identical to the C-terminal tripeptide of oxytocin, mimics some of the effects of AVP and its analog desglycinamide 9arginineS-vasopressin (DGAVP) on the central nervous system (el. the attenuating effect on puromycin-induced amnesia 31 and the facilitating effect on the development of physical dependence on morphine25). However, in contrast to AVP, PLG has a very low potency on active (De Wied, unpubl, observations) and passive (Bohus and De Wied, in preparation) avoidance test situations, and it facilitates heroin self-administering behavior z6. It, therefore, was deemed of interest to study the effects of i.c.v. administered PLG on a-MPT-induced catecholamine disappearance in rat brain nuclei. Male Wistar rats (130-150 g) received an i.p. injection of a-methyl-p-tyrosine methylester HCI (a-MPT; AB Biotec, Gfteborg; 300 mg/kg) 30 min prior to the intracerebroventricular (i.c.v.) administration of 1 #1 saline or 200 ng PLG in 1/~1 saline through a polyethylene cannula in the lateral ventricle which had been implanted 3 days before a. On the basis of behavioral studies, this dose of PLG can be considered to be approximately equipotent to that used in our previous study with AVP2L The rats were killed by decapitation 3 h after the saline or PLG injection. The brains were rapidly taken out and frozen on dry ice. Serial sections of 300 #m were cut in a cryostat at -10 °C. Nuclei were punched according to Palkovits 14 as described previously (see ref. 22). The tissue, pooled from 2 brains, was then homogenized in 50 #1 0.1 N HC104. Protein was assayed in a 10/~1 sample of the homogenate according to Lowry et al.lL Noradrenaline and dopamine were assayed as previously described 24 in 20 #1
Starting Page	561
Ending Page	566
Page Count	6
File Format	PDF HTM / HTML
DOI	10.1016/0006-8993(78)90368-2
PubMed reference number	647380
Journal	Medline
Volume Number	143
Alternate Webpage(s)	https://api.elsevier.com/content/article/pii/0006899378903682
Alternate Webpage(s)	https://www.sciencedirect.com/science/article/pii/0006899378903682?dgcid=api_sd_search-api-endpoint
Alternate Webpage(s)	https://doi.org/10.1016/0006-8993%2878%2990368-2
Journal	Brain Research
Language	English
Access Restriction	Open
Content Type	Text
Resource Type	Article