Chronic propranolol treatment in developing rats: acute and lasting effects on monoamines and beta-adrenergic receptors in the rat brain.
During early postnatal development rat pups were treated twice daily with the beta-adrenergic antagonist propranolol (15 mg/kg) in order to study the acute and long-lasting effects of early blockade of noradrenergic beta-mediated neurotransmission. Treatments from postnatal days 1-10 or days 11-20 did not induce alterations in the number of beta-adrenergic receptors as measured three days after the last injection, nor could lasting effects be shown at 60 days of age. The day 1-10 treatment, however, had a significant effect on the regional brain levels of noradrenaline (NA) and its metabolite 3-methoxy-4-hydroxyphenylglycol (MHPG), measured 90 min after the last injection. The metabolite had increased by 40% in all brain regions examined. On day 60, the MHPG concentrations were still increased when compared to postnatally saline-treated animals. Propranolol treatment from day 11-20 only marginally increased MHPG on day 20 and induced no lasting differences. These results suggest that propranolol treatment during the first ten days of life produces a long-lasting increase in NA metabolism, possibly reflecting an increased neuronal NA turnover.
Erdtsieck-Ernste
E B
EB
Netherlands Institute for Brain Research, Amsterdam.
Feenstra
M G
MG
Boer
G J
GJ
van Galen
H
H
D000818:Animals; D000831:Animals, Newborn / Q000502:physiology*; D015306:Biogenic Monoamines / Q000378:metabolism*; D001835:Body Weight / Q000187:drug effects; D001921:Brain / Q000187:drug effects* / Q000254:growth & development / Q000378:metabolism; D005123:Eye / Q000187:drug effects / Q000254:growth & development; D011433:Propranolol / Q000494:pharmacology*; D051381:Rats; D011919:Rats, Inbred Strains; D011943:Receptors, Adrenergic, beta / Q000187:drug effects* / Q000378:metabolism; D013997:Time Factors
D015306:Biogenic Monoamines; D011943:Receptors, Adrenergic, beta; D011433:Propranolol