The pineal eye of the lizard (Anolis carolinensis), a photoreceptor as revealed by oxygen consumption studies

Abstract

Numerous investigations have been carried out in an effort to determine the significance of the pineal eye as a photoreceptor. Francotte (1897) cauterized the eyes of the lizard Anguis fragilis and tested the receptive functions of the pineal eye. His results, while inconclusive, suggest that this organ may act as a light receptor in this species of lizard. Nowikoff ('07) studied the effect of light on the pineal eye in the lizards Lacerta agilis and Anguis fragilis and showed that the movement of pigment granules in the retina of the pineal eye was dependent upon the intensity of light used as a stimulus. Dendy ( ,ll) focused a light of relatively high intensity above the pineal eye of the Rhynchocephalian Sphenodon punctatus and failed to observe any resulting influence. Clausen and Poris ('37) showed that the pineal of Anolis carolinensis was not the primary avenue of light reception for testis activation but that obliteration of the pineal eye resulted in an accelerated testicular activity. It was suggested in this investigation that light reception through the pineal eye might however act as a n inhibition of testicular activity by some indirect means.I n the following series of experiments an attempt has been made to determine, by comparative oxygen consumption tests, whether o r not the pineal eye served as a photoreceptor in the lizard Anolis carolinensis. Throughout the following discussion we will use the term pineal and restrict its use herein to that specific structure of the ephiphyseal complex generally referred to as the parietal eye in most reptiles. A preliminary report of the results was published in abstract form (Clausen and Mofshin, '36).

The Pineal Complex and Thermoregulation

“…Parietalectomy, however, has not been conclusively shown to alter metabolic rate, although many factors such as season have not been taken into account in the few studies reported. Clausen & Mofshin (1939) found that the oxygen consumption of lizards (Anolis carolinensis) was lower in normal animals exposed to darkness than in those exposed to light. Various combinations of surgical procedures including parietalectomy, eye enucleation, and covering the dermal photoreceptors, elevated the oxygen consumption measured in darkness.…”

Oxygen Consumption in the Lizard Uta Stansburiana

“…Reptilian physiologists have seldom stated the time of day at which they made their measurements, and have not, as a rule, specified light conditions during their experiments. The paper on light effects by Clausen and Mofshin ( 1939) and numerous studies of cyclical activity in reptiles (Hoffman 1957, Evans 1966 as well as studies of cyclic changes jn metabolism of other animals (for example Heusner 1956) indicate that significant differences may be involved. Such details, though of little significance in documenting the long range effect of size, are nevertheless of particular concern when comparing nocturnal and diurnal species, or hibernating versus nonhibernating individuals.…”

Optimal Body Size in Lesser Antillean Anolis Lizards‐‐A Mechanistic Approach

“…RMRs measured in Anolis carolinensis resting in the light were found to be 50% greater than those measured in the dark (Claussen and Mofshin 1939), so that a minimum FRMR index would be 1.25, considering an animal spending half the day in the dark, half in light. Bartholomew and Tucker ( 1963) reported minimal and maximal RMRs measured in Amphibolus barbatus which differ by a factor of about three.…”