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Biomedical subjects

R Shukla

Publications and source records attributed to R Shukla.

At least 181 records · Page 10Linked to original sources
PubMed1981

The effect of intracerebroventricular administration of catecholamines and their antagonists on rectal temperature of Mastomys natalensis.

Noradrenaline (NA), adrenaline (ADR), isoprenaline (ISO) and dopamine (DA) were given through a chronically implanted cannula in the lateral cerebral ventricle of Mastomys natalensis. Low doses of NA (0.05-0.25 microgram) reduced rectal temperature while larger doses (0.35 microgram upwards) produced dose-dependent hyperthermia. The hypothermic effect was antagonised by alpha-adrenoceptor and the hyperthermia by beta-adrenoceptor antagonists. alpha-Methyl noradrenaline produced less hyperthermia but it antagonised the hyperthermic effect of NA. Adrenaline (0.1-10 microgram) was ineffective per se but when given after tolazoline it produced hyperthermia and after propranolol it produced hypothermia. The dose-dependent hyperthermia with isoprenaline (0.1-10 microgram) was blocked by propranolol and MJ-1999. Dopamine (0.5-20 microgram) and its agonists apomorphine, amantadine and BS 9641 produced hyperthermia which was antagonised by haloperidol and pimozide but not by alpha- or beta adrenoceptor antagonists. Noradrenaline (1.0 microgram) produced hypothermia at ambient temperature of 10 degrees C and 16 degrees C. It had no effect at 20 degrees C which seems to be the thermoneutral zone for mastomys. The hyperthermic effect at 33 degrees C was less than at 24 degrees C. Dopamine (10 micrograms) response was attenuated at 33 degrees C and unaffected at other ambient temperatures. It is concluded that alpha- and beta-adrenoceptors and DA-receptors exist in the central thermoregulatory mechanism in mastomys. The alpha-receptors are concerned with lowering the body temperature whereas the beta-receptors and DA-receptors are involved in raising it.

Adrenergic alpha-Antagonists↗