Differentiation of alpha-adrenergic responsiveness in the neonatal rat iris after decentralization or extirpation of the superior cervical ganglion.
The effects of stimulating alpha-adrenergic receptors in the iris of neonatal rats (up to 30 days of age) whose superior cervical ganglion (SCG) has been decentralized or extirpated 3 days after birth were investigated by measuring changes in pupil diameter. The responses of these experimental animals were compared with those of normal animals of similar age. Alpha-adrenergic stimulation was effected by topical application of noradrenaline (NA) after blockade of beta-adrenoceptors with dichlorisoproterenol and cholinoceptors with atropine. The results reveal that although decentralization of the SCG depletes the NA content of the ipsilateral iris as demonstrated by radio-chemical assay and formaldehyde-induced fluorescence, it does not affect the development of alpha-adrenoceptor responsiveness. Even the more severe disruption of the innervation caused by extirpation of the SCG did not affect the responsiveness of the ipsilateral iris.
D000375:Aging; D000818:Animals; D000831:Animals, Newborn; D001921:Brain / Q000502:physiology*; D005260:Female; D005728:Ganglia, Sympathetic / Q000502:physiology*; D007498:Iris / Q000254:growth & development / Q000502:physiology*; D008297:Male; D008856:Microscopy, Fluorescence; D011680:Pupil / Q000254:growth & development / Q000502:physiology*; D051381:Rats; D011941:Receptors, Adrenergic / Q000502:physiology*; D011942:Receptors, Adrenergic, alpha / Q000502:physiology*
D011941:Receptors, Adrenergic; D011942:Receptors, Adrenergic, alpha